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Lathe - Motor

 
 

 

 
 
Survey - What Size Motor for 9" Southbend (Feb 18, 2001) Problems starting lathe (Aug 15, 2003)
Need a Motor (Feb 26, 2002) 3 phase? (Aug 25, 2003)
3 phase motor vs. single phase (May 3, 2002) Power King motor (Sep 10, 2003)
10" Toolroom, 110/220 (Apr 22, 2002) Electric Motor Frame Sizes (Jan 5, 2004)
220 (Jul 24, 2002) Motor size limit for 11" lathe (Jan 8, 2004)
Three phase 440/220 (Nov 16, 2002) 16" motor horsepower (Jan 9, 2004)
Motor Replacement?  (Dec 1, 2002) Maximum Power for Heavy 10? (Mar 8, 2004)
Relocating the motor drive on a 9" (Dec 6, 2002) New motor HP and RPM maximum (Apr 13, 2004)
Bodine motor data (Mar 13, 2003) SB 9 replacement motor help (May 5, 2004)
New motor for SB 9" A (Mar 5, 2003) 9 in Motor Selection (Jul 7, 2004)
Electric motor (May 3, 2003) Heavy 10 motor replacement (Jul 27, 2004)
SB 9 motor (May 7, 2003) Motor Choice for 13" SB? (Jul 30, 2004)
DC Motor conversion (Jun 10, 2003) Heavy 10 Motor Change? (Aug 12, 2004)
Lathe motor base/mount (Jul 20, 2003) South Bend 9A Motor Voltages (Nov 16, 2004)
S/B Motor size (Jul 29, 2003) Model 9A motor replacement (Nov 29, 2004)
Motor recommendations needed (Jul 31, 2003) New Motor? (Dec 14, 2004)
Motor - Single or 3-phase? (Aug 5, 2003) Motors/controllers: too many choices (Feb 11, 2005)
 
Survey - What Size Motor for 9" Southbend
I would like to here from all of you 9" guys on what size electric motor you are using. I have seen 1/4HP to 1HP used. I have a spare 1/3HP and I am not sure if it is heavy enough to use. Jim (233)
For over 20 years I used the same old 1/4hp washing machine motor that came with the machine when I bought it. I recently replaced it with a new 1/2 hp capacitor start and run 1750rpm from HF and it fits a little tight but works. Actually I could jump the belt off the pulley as easy with the old motor as the new one. The rear of the motor shows fairly well in this picture. It fills the area very well and I would not consider putting a larger one in there. JWE (241)
I picked up a used 3/4 HP 1P G.E. 1150 RPM cap-start/cap-run motor to use on my 9". I chose the lower RPM since I'll be making the pulleys for the motor/counter shaft. (mine had non-standard pulleys. No real idea how 3/4 HP will do yet, but it should be okay since its an American-made motor. I've got it wired for 220, of course. Paul R. (247)
I just checked my 9" and it is running with a 1/3hp 110v motor and I have had no problems at all. Yesterday I talked to South Bend and they said that even the Heavy 10 was shipped out with only a 1/2hp motor, so you should be able to use a 1/3hp with no problems. Karl (263)
Need a Motor
I need a new Motor for my 9x36 South Bend Lathe. It now has a large 1/4 horse Westinghouse With B145K frame with a 5/8's inch drive shaft 3/16inch key Instant reverse. Dose any body know what the motor number would be in the Grainger catalog. I would like to stay a 1/2 Horse or less (1/3or 1/4). I can make a adaptor plate to mount it to the frame if needed. Or dose any one have a better idea on where I can get a motor. Chet (3412)
Have you tried a local motor shop? Often they have used motors that they have gone through for cheap. you can call Grainger and they will cross reference the motor. However, it sounds like the motor you have is not the right size. FWIW: I called Southbend and talked to I think randy, and he said that to replace it with a 1/2 horse motor, 5/8 shaft, shaft length ??? 1/2 horse max otherwise you will toast the headstock bearings. Sounds like decent enough advise. I bought a lesson from the local motor shop. I made the mistake of getting plain 56 type frame, welded to the base of the motor. Was a royal pain to get in because of clearance issues to get at the bolts. Price was $120, about same as Grainger, plus I got the support locally. I don't know the NEMA mount number, but get the kind that has a separate base from the motor and clamps the motor at the ends with collars. makes life now and hereafter MUCH easier. dennis (3413)
Why would a larger motor hurt the headstock bearings? I have a 3/4 horse on mine (what I had on hand at the time) and I don't seem to have any problems with bearing heat. Frank (3414)
Dumpster diving is a good source for working motors, old dryers, washing machines etc often are tossed when the motor is still good, but other parts have worn out. Don't try a vacuum cleaner motor though as they are usually much too fast for lathe or machine use. John (3428)
Dryer motors probably even have a decent mount to go with them (I see a LOT of them in a day) Very seldom do dryer motors ever burn out. Maytag's rule! Matt (3429)
My little 9" has a 1/4 h.p. motor on it and the other night I decided to see how heavy a cut I could take with it. After playing with the feed rate and sharpening the tool just right, I was able to take a .200" cut off a three inch diameter piece of mild steel! the belts never slipped and I thought about trying for more but then thought ...... why? the feed was fairly slow and the spindle speed was the slowest you can go with out using back gear. These little lathe are tough and will do the lions share of the work if you take your time and set them up right. Charles (3430)
3 phase motor vs. single phase
I have a new 10k (well, 1954 new). It currently has the 220v 3 phase 1/2 horse motor. I've found the following on eBay and I'm wondering if this would be a 1:1 replacement. I know I may have to work on re-drilling some holes... "South Bend 9" Lathe single phase 1/2 Hp motor (reversible), Dayton capacitor start. Works with 9", 10k, heavy 10 lathes. Motor is 110v, good used working condition. If you need the Forward/Reverse Control see my other auctions." Steve (4178)
That motor was originally purchased from Granger supply. Dayton is their trade name just like Craftsman belongs to Sears. Check on the price with Granger before you buy a used motor. You might find very little difference. There's nothing like a brand new motor. RC (4179)
Steve, keep the 3 phase motor and consider powering it with a VFD. It will run your 3 phase motor off of single phase 220 and provide a host of other features such as variable speed. Smoother drive too. Do a search on VFD's they are available as surplus. Steve (4181)
Steve, Sorry, while I'm handy on the computer and should be able to find the info, can you help me out with a bit more info? I'm guessing this means "variable frequency drive", but I don't know what else I'm looking for. Can you help me out with some more details? I've had an offer from a guy a couple hours away to help me build a rotary phase converter, but I know so little about this stuff... AND, I spent all my cash (well, all that the wife will let me spend) on the lathe so I'm trying to keep this piece cheap if possible. (4182)
I recently bought a VFD (variable frequency drive) from eBay, for $100. This drive was for up to a 1hp motor, so it is larger than the one that you would need (probably 1/2hp or 3/4 hp) for a Heavy 10 lathe. Here is the link to an auction for the same drive that I bought from these people: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem item=1727711565 If you want to go the cheaper route and just switch to a single phase motor, then I think that just about any US-made used 1/2hp or 3/4 hp motor of the right size should be OK. The wiring diagram for reversing the direction of the motor should be on a plate on the motor housing. The auction that was posted on this group for a "south bend lathe motor" was not particularly special... There are several classes of enclosures for electric motors. I think that the most common is "TEFC", which stands for totally enclosed fan cooled. This should be OK for an under-the-cabinet lathe motor. Motors for harsher environments might be called "TENV" (totally enclosed non-ventilated). Another one is ODP (open drip proof), which also should be OK for a lathe. There are specific dimensions for sizing with "NEMA" numbers that correspond to particular dimensions. Information can be found on the www by doing a search on www.google.com  , with phrases like, "electric motor", or "variable frequency drive". You should be able to find a good used 1/2 hp or 3/4 hp motor, 1725 rpm, from a motor repair place, a used tool store, or a garage sale, for $20 or so. Jon (4183)
Steve, Try this site: http://www.chaski.org/homemachinist Run a search on the archives with the letters VFD (variable frequency drive). A VFD will do a lot more for you than a rotary converter ever will. There NOT power hogs and your 3 Phase motor will actually give you a better finish on your work.( It doesn't tramp like a single phase motor does. Also check out the practical machinist site. A lot of VFD info here. Its true 3 phase from single phase power. Steve (4188)
Steve, Here is the Practical Scoop! http://www.practicalmachinist.com  Steve (4189)
10" Toolroom, 110/220
In the process of buying 10" toolroom. It is currently wired for 110 volts. Would there be any advantage to rewire for 220 single phase? (In my home shop, don't have 3ph. available) and don't want to mess w/converter. Darren (4020)
Not much to be gained by rewiring for 220 for a small induction motor (1.5HP or less). I do like running all my big stationary power tools on 220, however. They're more efficient, faster starting, and the lights don't dim with 220. I currently have my 10" table saw, 12" radial arm saw and my 9" South Bend running 220. I still need to run 220 power for my mill/drill (2HP) and Delta wood lathe (1.5HP). Another reason to run 220 is if you ever wanted to put an inverter drive on the lathe. That's what I did and I love it. Paul R. (4021)
The only reasons you may want to think about rewiring would be if you need a bigger motor that is only 200, or if you have a problem that your existing (shop) wiring cannot handle the load on a 110 circuit. if you need a separate circuit for the machine ( always a good idea in my book) then it's only a little more expensive to install it for 220 but there is often no real advantage to doing it that way. if the machine makes the lights blink or causes other power disturbances when you start it or when loading it up, or has very poor power under loading, then you need a separate circuit. if it's on a circuit of its own and still does that, then going to 220 may help by reducing the load on one phase, then again, it may not. -this somewhat depends on how your shop is wired. Don't expect a converter to help much of this either, if the shop wiring is at fault there is not a big chance that using a converter will make the machine immune to the problem. bottom line with these is - if you don't have a reason to need it, then expect little gain from doing the conversion, and you probably will see no difference in the machine performance. if you need it - then you probably should expect to make some upgrades or changes in the shop wiring too. you need an electrician to look at the wiring you have to see what the actual situation is doing. If you have any nearby acquaintances of this kind, many ham radio operators or industrial electricians could walk you thru this in a few minutes of looking and testing, then tell you what needed changed. an older but still informative, general rule is that over 1 HP is usually on 220 but many plug-in (shop) appliances and tools make lies of this now. A lot of the older equipt was usually 3/4 HP and under on 110, higher HP on 220, seldom used three phase unless used in industrial environment and usually then above 2 HP. (4022)
220
My lathe (Model A) hasn't shown up at the door yet, but when it does I will be converting it from 220/3ph to 110/1ph. Does anyone have advice to offer before I burn my money? Flash (5359)
I converted my 1941 A to a VFD/1 HP 220 volt-3ph with a package from Dealers Electric. I got spoiled by the variable speed on my little 7x10 mini lathe. I love the soft start/quick stop as well as the variable speed (within reason). I don't think you'll find a 120 volt VFD though, and since you said 120 volts, just get a 1HP max 1720 RPM reversible, capacitor-start motor, preferably TEFC (Totally Enclosed Fan Cooled). If you can stay at 220 volts, just buy a VFD for around 100+ bucks and you're good to go. All that being said, people get away with using any old motor (even an open frame washing machine motor). Probably no help whatsoever. Paul R. (5360)
Is there any danger to the lathe from up-gunning to a full hp? Last but not least, why would I want one to be reversible? Flash (5361)
Should be fine if you're running with a flat belt (leather or synthetic). It slips well before something really expensive would break (except flesh and bone). Probably can't transmit a full horse via a flat belt anyway. Paul R. (5362)
Nope just remember to keep the motor V belt or flat belt pulley the same size this will keep your top speed the same as stock. as for too much HP, I put a 1.5 HP motor on my 9" and have no problems other then pulling more amps. The belt drive keeps you from doing damage. kerry (5365)
I just went through the same thing 3 weeks ago. If you can swing it, go with 220v single speed, you draw less amps, smaller wire, etc. Your house ( shop?) probably already have it for the dryer, stove, water heater, etc. Several people from this group home machinist page said to go at least 3/4 hp (mine had 1/2 3-phase) and that 1 hp would be better. I spent $2 each on a 3/4 hp open drip-proof and a 1 hp TEFC. The latter needed a new bearing ($9)and both needed a bushing (pulley was 3/4", motor shafts were 5/8") for $3. Seems to work okay. Most 22v single-phase motors can also be wired for 110v, and can be wired to run in either direction. I managed to set mine up the wrong way. Reversing is needed to cut metric threads, but several people advised me to not hook mine up that way because the chuck might spin off if you reversed it without stopping first. (5372)
I'm trying to visualize why reversing has anything to do w/ metric threads. I'm also trying to visualize wanting to cut a metric thread. :-] I am stuck with 110 because I don't have the service capacity to run both into my garage and Lights, drill press, dremel tool, fans, shop vac, compressor etc., etc. have to have 110. (5373)
The phase issue, I wouldn't waste time and money changing out a good 3 phase motor and control panel/switch. Stick with 220V and spend the money on a VFD if you have it to burn. If saving is important, get a free 3 phase idler motor from the scrap yard, wire it in the system, and start it with a pull rope to provide your 3 phase conversion. There are plans all over the net, probably even in the archives here to make one as basic or as sophisticated as you want. Keeping 3 phase is nice for a lathe because of the instant stop, start, and reverse ability. OTOH, if you really feel more comfortable with it, 1 HP single phase motors aren't expensive. Good luck either way. Hope your new lathe is "better than you expected" when it arrives! smt (5374)
You don't "have" to. But since most lathes don't have metric threading dials, which require different gears for different pitches, the only effective way to avoid losing your thread, is to back out the tool a few thousandths at the end of the cut, and back (reverse) the lathe up to the starting point, dial the bit back in again, start cutting, and feed in the next increment. If you disengage the halfnuts while screw cutting, it can be "difficult", especially with very odd, or metric, threads, to re-engage them with the tool in the same axial position. I.e., back exactly in the last cut thread as opposed to a little bit sideways, one way of the other, destroying the thread. well, I'm with you there. Camera equipment, or Japanese motorcycles... run both vac, If you are saying you need to run one line, then use split 230 volt. You get 230 across the 2 hot leads (red and black), and 115 between both red and neutral, and black and neutral. Just balance the system so that about 1/2 the 115 load is on each leg. Also, do use proper wiring, and grounding. The best way is to run the 230 to a small sub panel. Then take off what you need, in whatever form (115 or 230) you need, from there, sizing the wire for each circuit as appropriate. You will get more load capacity for your wire size running it that way. In fact, given what you mention running, if all on at once, you may not have the ampacity on say 10gage wire to run a long branch on only 110v. smt (5375)
When you put on the metric change gears, you get oddball ratios such that the thread dial is no longer effective. Therefore, you must reverse rather than open the half nuts. (5376)
As mention above you can't use the thread dial to cut long runs of metric threads on an American lathe Although you could re-engage the halfnut on the same number for short threads that are not critical. But the safe way to go is to back the tool out and reverse the machine to feed it back to the start. Now if you lose tracking on a thread there is an easy way to pick it up. set your compound to be 90 deg to the cross slide this will allow you to feed the compound backward or forward as needed to pickup the thread. the down side is that now you have to feed with the cross slide. As for reversing a single phase motor, You can't throw it into reverse like a three phase motor where it will slow then reverse no matter the speed. A single phase motor needs to be almost stopped to be reversed if not it will just keep going the same direction, unless you buy a instant reversing motor and that's another story. Kerry (5379)
Flash; One HP isn't overkill. As to being reversible - well... Some folks like to have a reversible spindle, it's particularly useful if you do toolpost grinding. The downside is that with a threaded spindle, when running in reverse, a tool catch can spin a chuck right off. Reversing direction can give a bit quicker or better results when polishing turned work as well. There is one other time reversing motors shine. When doing some threading operations, you may not want to open the half nuts, as you've set up the gear train in a way that the thread dial doesn't work in quite the usual way, or you don't have a threading dial. It's a darn sight easier to stop the lathe and run the carriage back under power than to hand turn the spindle backwards, particularly if doing a long and coarse thread. Instant reversing (3 phase) motors add more fun, more than one person has hit the wrong button, seen the chuck start to spin off, hit the forward, and heard a loud thunk as the chuck spins onto the spindle hard. In bad cases, you end up turning off the back plate. In really bad cases something expensive breaks. Stan (5384)
Flash: I was recently in the same position as yourself, with the added complication of not having a permanent base of operations (house hunting is ongoing). Although on the pricey side of things, AC Tech makes a VFD (variable frequency drive) that will take either 110 or 220 single phase input and convert it to 220 3ph, with variable speed and reversing to boot! It cost me $175, but now I'm able to get the best of all worlds no matter what power is available. Tom (5386)
Three phase 440/220
Does anyone know if you can change a 3-phase motor that is 440 down to 220 3-phase. There is no tag on my motor, just the electric box tag, which reads 440. Or would it be easier to change my Balder phase converter to 440 (from 220)? (7328)
It's easy, if not a motor winding shop will make the winding taps for you. 440v= hooked together 4 7 5 8 6 9, line on 1,2,and3. 220 v= hook together 4, 5 and 6, one line to 1 7 one line to 2 8 and one line to 3 and 9 (7331)
This is done with an ohmeter. If the motor is 440VAC the field windings should be in series for each phase; they should be reconnected in parallel for 220VAC. (7354)
Motor Replacement?
I picked up a 10" SB at an auction Saturday. It is in pretty good shape from what I can see so far. The ways show a little wear - you can feel it but not see it. From what I've been able to learn so far, it is a bench-mounted 10" toolroom lathe from the early to mid forties (Cat #8187YN; Ser #170216). It has the taper attachment, 5C collet attachment (handwheel), threading attachment, and a 6" 4-jaw Buck. It's missing the toolpost. I couldn't believe I got it for $350 - especially after a small, beat-up Enco mill went for $750! Anyway, it has what looks like the original Westinghouse 3/4HP 220/440V 3 ph motor. Is there any reason I can't replace that with a nice little 1 - 1.5HP 110V single phase motor? Any "gotchas" I should watch out for when picking a motor? Wallace (7671)
I don't there is much to it. Mounting hole match, overall dimensions, shaft diameter are so things that come to mind. I think its been done a lot. I'm trying to go the other way, though, so you Wallace, or anyone else out there who finds themselves with a spare 1/2 - 1 HP 3 phase motor off a SB lathe or other, I may be interested in your motor. Rick K. (7676)
The 9" SB that I have came with a 1/2hp (IIRC) 3 phase motor. Currently I'm using a 1/2 capacitor start 110v motor (off my air compressor). I have another 1/2 motor but it is not capacitor start, the mounting holes and shaft are also different. As I would like to get my air compressor going again I'm wondering if the other motor will work on the lathe. I doubt that it would have the starting torque required for the compressor but it might have enough for the lathe. The capacitor start motor has lots of torque and I can squeal the belts if I have a heavy piece mounted. Before I start modifying the mounts and making a pulley bushing I thought I'd check with the group for their expertise and experience. John (7677)
John, Your compressor motor is likely to be 3450 RPM, as most are. For your lathe, you need a motor that turns at 1725 RPM, and a half horse or better; either capacitor start (preferred), or split phase (no capacitor). Ideally, however, you may want to have a 1/2 or 3/4 horse DC motor or VFD (variable frequency drive, 3 phase) motor/control, for easy and convenient speed regulation. The later options come at a price, but if you shop around, you may find something within your budget.  Norman (7679)
Norman My compressor motor is 1725 RPM, that might explain why it is so sloooow, the tank is also too big, but the price was right. If my non-capacity motor has enough torque then I'll go ahead and make it fit as I need my compressor back. I'd love to have variable speed but I'm a newbie and am still learning the basics so I can live with the cone pulley adjustments for now. John (7681)
John Just a thought if you could get a couple of bolts in and get the pulley tight enough so it wouldn't t slip you could put a heavy chunk of iron in try starting it. It would shake pretty bad with the pulley off-center but you wouldn't have to run it that way; just see if it will start and if it does start OK then make your modifications. Lew (7682)
Relocating the motor drive on a 9"
I'm going to be relocating the motor drive on my 9" from horizontally mounted behind the lathe to overhead. As part of that, I'm going to be building a mounting frame out of u channel to hold the lathe and the motor drive setup in the proper orientation. I'm thinking this will just be a piece of horizontal u channel that the lathe bed bolts to, with another horizontal piece coming out the back of one end perpendicular to the lathe bed, and a vertical piece rising off that to provide a mounting location for the motor drive pivot plate. Oh, and some diagonal braces to help hold everything rigidly. How anal do I need to be about ensuring that the drive pulleys are in line? Are the flat pulleys leather belt super sensitive to misalignment? I'm wondering if I need to just be careful to ensure that things are in line when I build the mounting frame or if I need to build in fine adjustment capability. Mark (7804)
I recently redid mine and holding the accuracy possible with a combination square and a pencil was plenty. I would brace it though. (7822)
Actually, I'm in the process of swapping with a friend who has welding capabilities for a new bench...leaning [no pun intended] towards a bench that just looks like a giant channel-stock sawhorse, with another piece of channel stock coming up from behind the headstock and leaning back about 30 degrees off vertical, and a brace running from the upper end of that to the foot below it, forming an obtuse triangle as viewed from the end. The triangle is the strongest structure--you can't change an angle without changing one of the sides' length, which is not true for anything with more than 3 sides. I figure if I slot the channelstock horizontally to provide adjustment in one axis and the countershaft-support foot is already slotted to provide adjustment in the other axis, it ought to be a done deal except for adjusting the belt length. I'll post a pic or two when it's done.(7823)
Have you looked at the transmission tables that Harbor Freight sells ? They're steel tables with a large grate that covers a drain pan the full size of the table. With a weight rating of something like 1000lbs you could put both a lathe and a mill on one of them and have a great setup for coolant use recovery. Overkill for the mini-lathes but a good size table for a Southbend or a mill. Dave (7826)
A buddy and I whipped up a 'bench' out of some channel misc. steel that was laying around this weekend. It mounts the motor overhead, greatly reducing the depth needed for the lathe. I'm very happy with how it turned out except that the drive pulley's oil can drip down onto the lathe. I'll have to rig up some oil catchers. Other than that, it turned out great. Stuff that was a bit more tricky than a regular job was that we needed to reposition the belt tensioner to get the handle away from the chuck, and we needed to use some 90 deg. 1/8" pipe fittings for the drive pulley oilers. A pleasant surprise was that the drive pulley isn't right out in your face. I was originally thinking I'd need to fabricate some type of guard, but its well away from your head, so I can skip that. *pictures no longer available* We took some cuts after we got it all together (first ones for me with this machine!). No chatter or anything taking an .080 cut in AL at high speed, so we're thinking the new mount is plenty rigid. Certainly its a lot more rigid than the metal desk it was mounted on before... :-) In the coming weeks I'll use a strut rod to check level / bed twist and make up the oil drip trays, but I'm definitely happy with the new mount setup. Mark (7853)
Well done! Interesting solution to a common problem. In my imagined version, since I have a floor pedestal, I'd be building the counter-shaft pedestal from scratch, and use sealed ball-bearings. That would eliminate the oil problem. I also don't think I would bolt the head stock to the vertical member. Anyway, thanks a bunch for the report and pictures of your hard work. Sounds like you've got a nice setup now. Helps me figure out how I might do mine. Paul R. (7876)
I'll have to look at it with the goal of changing the bearing type. As an added bonus, there'd be one last thing to oil. What would concern you with bolting the vertical member to the headstock? Mark (7879)
Mark, My concern is that there could now be a new source of motor vibration and deflection on the head stock. Think of the head stock as a pendulum swinging on the ways. The new side-to-side motion directly translates into surface finish on the work piece. Probably more paranoia than anything else, though ;-). On the other hand, having a belt pulling vertically rather than horizontally would tend to reduce this effect. Lathes on line-shafts or UMD's probably turn smoother (microscopically). Paul R. (7898)
Bodine motor data
Motor experts in the group, I need some help in determining the connections for the start and run capacitors and power-in connections for a Bodine gearmotor I purchased for my die filer. Bodine tech support tried to fax the data sheet but my FAX machine failed. They seem reluctant to answer my e-mail or re-send now that I have replaced the FAX. Dave (9752)
Mike Smith's response made me go back to the Bodine site and look again for motor data. The key is to use the motor's first 2 numbers and the following letter in the search from the home page. In my case, I searched for a 44C motor and came up with 2 publications totaling 52 pages. I was originally trying to input the whole model number then smaller and smaller parts but gave up before getting down to 44C. Thanks to all of you who helped. Bodine did re-FAX the spec sheet that originally didn't come through. So I have my data. Dave (9766)
I have posted the Bodine 44C Motor Wiring Diagram in the Files Section of the Yahoo Mill_Drill Group for those who expressed interest a few weeks ago when I posted a question. The diagram is a composite of what Bodine sent me and my own measurements and observations. It is in .WMF format which I converted from the AutoCAD original where I created it. Dave (9834)
New motor for SB 9" A
Thinking about replacing the 1/3 hp single phase motor on my 9" Model A lathe with horizontal drive. Any suggestions about what motor to switch to? I'm thinking TEFC 3/4 hp or 1 hp single phase, 1725 rpm, 115V or 230V, 56 frame. Is this too much motor? Should I consider a 3600rpm motor to gain spindle speed? VFD driven 3-phase to gain variable speed is a possibility, I have an 1.5hp motor 3 phase motor already, but would need to purchase VFD. What do you use on your SB 9"? mark (9632)
Mark A 3/4 HP will be just fine. I would stay with the 1750 RPM motor You can consider using a DC motor and variable speed controller if you ever have a need for higher speeds??? or it is really good for lower speeds. Clint (9633)
I have a 1/2 hp on my 10k and it is just a tad too little. 3/4 or 1 hp is a better choice. If I ever bother to change motors, I will go 1 hp. Frank (9634)
Mark, Mine was built with a 1/2 HP/1725rpm motor. That's plenty enough. RichD (9636)
Mark: For a 9" lathe, a 3/4 HP motor will do very well for you! I have used 1 HP a couple times but have never felt that it was needed. Do not make the mistake of using 3450 RPM. You will never be able to get your machine to run slow enough. Even if you choose to use carbide tools you will get all the speed you need with a 1725 motor. If you can afford to go the VFD route, that is the Cadillac of drives but they are very expensive. Desmond (9638)
Electric motor
The GE electric motor on my SB 9 has given up on me. The last time I ran it, smoke came out of it and as an old electrical engineer once told me, when you lose the smoke, you need to replace the motor. There are no tags on the motor to give model number, HP etc, so would appreciate any help in what manufacturer, type, hp, etc I need to get for replacement. I did take the old motor apart just in case it could be fixed and found a lot of corrosion inside on the windings and shaft so think it is time to get a replacement. Are there used motors available? Barry (10745)
Grainger's does stock an exact replacement. Mine came with one. It's a 1/2HP capacitor start, ball bearing type. A couple of months ago, suddenly smoke came out of mine, also, but I was lucky. I was turning copper and by some bizarre chance a fine turning got into the air intake of the motor and found its way either to the starter contacts or the terminal block! In a panic I got the nameplate (It is around here somewhere) and checked it at Grainger's online catalogue and did locate it. I shall find it again and post the stock #. Used ones do turn up on E-Bay, but the ones I have seen, the sellers seem to be aware of the prices of new ones. (10746)
Grainger's lists a couple: # 4K781 @ $ 168.25 and #4K142@ $ 179.50. However, there are some on E-Bay, including http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem item=2527756629 category=1272 which is right now at *ten dollars*. You might have to bush the pulleys, etc., but the ratings are right and the frame looks like the right type, comes off a 12" Craftsman lathe. There are lots of motors on there so you should be able to avoid paying the New prices. (10747)
I buy 1700 rpm capacitor start 1/2 hp motors as I find them at flea markets etc for 20-25.00. (10748)
Barry, Myself, I would try to buy a new motor from Grainger. (10750)
In the back of a Grainger catalog there are direction for measuring a motor to find the frame size. it is very straight forward and easy to do. LaRue (10751)
Harbor Freight has on on sale @$79.99. Ball bearing and reversible. Jim B (10752)
Wow, that sounds like a great deal! Is it Ball Bearing? (10753)
You can get a surplus 1/2 HP 3 phase motor for less than $50.00 and a variable speed drive from e-bay for less than $100.00. easily the best way to replace the motor. In a pinch, consider a washing machine motor if you can't wait. 1.2 seems to be the normal, but you could use 3/4 with no loss. I would go for a compressor rated cap start cap run - reversible motor if I was to stay with an AC motor. Dave (10756)
Try http://www.surpluscenter.com they sell almost any type motors there is, at really good prices also. Clint (10762)
The motor in question is reversible, true - but I thought that an "instant reversible" motor is required. Can someone comment on whether or not this is true? These motors are much more expensive. Denny (10779)
You do not want an instant reversing motor. If you already have one it will work but it will tear up the machine and the belts. Think about the inertia of the chuck and gear train moving at a few hundred RPM grinding to a halt and instantly starting up again. There are no operations that need instant reverse, Most 3 phase motors are reversible. max (10780)
Just to clarify. My lathe currently has a 3-phase motor, which is essentially instant reversing, right? If I replace it with a 1-phase motor (not instant reversing), I can still use a switch to run it in reverse. I just have to wait for it to stop, first. Is that right? If so, what type of switch should I be looking for? Denny (10793)
I am an old electrical engineer. The smoke is what makes things work. When the smoke goes away, things stop working. Another rule of thumb, don't blow away the smoke. The smoke tells you what is wrong. Glen (10797)
Caution - instant reversing on three phase motors causes a very stiff torque pulse in the driveline and can damage items very quickly. this will also spin the chuck off of the threads and toss it away from the lathe or batter the threads on the spindle and twist the tailstock of you have a workpiece between centers. You do NOT want to find this out the hard way - it is very dangerous. even with no chuck on the spindle, the energy stored in the inertia of the driveline may be enough to over stress your supports and brackets securing shafts and motor. There is no good reason to 'instant reverse" work in these era design lathes, whether you have a screw-on chuck or not - these machines were not made for it and are not safely tolerant of this practice. Even when furnished with three-phase motors, the workshop and toolroom machines had smallish motors ( 1/3 or 1/2 HP) compared to the retrofits we are talking about here. for my purposes,I find it is no great discomfort to let the chuck stop normally and then start the motor in the reverse direction. Reversing a three phase motor while under power is called ' plugging' and is responsible for a lot of damaged equipment. just because they will do it does not mean that it is safe or even a good idea to try. The motor and the electrical gear controlling it are normally specially sized for this duty, and the driven application is designed for the heavy torque load it imposes. even reversing a small 3-phase motor under load generates more heat in the motor and reduces the available duty cycle: the energy of the machine inertia is transmitted through the driveline to the motor's magnetic fields, which act as an electrical brake to absorb this energy and then accelerate the parts in the opposite direction. the majority of this energy converts to magnetic force and then to heat inside the motor. James (10821)
I agree with the above post on not reversing you lathe instantly or near instantly, but if you need to reverse your motor get an AC drive then use the braking and ramp up programming to slow down the spindle then slowly speed it back up in reverse. Most drive will allow you to set the braking and ramp up. braking is exactly that it slow the motor down faster then letting it coast and you can adjust how hard the "brakes" are applied. Ramp up is throttling the motor more slowly then just flipping a switch and giving it everything at once. it brings the motor up to full speed over a few seconds instead of as fast as it can. This can help to start big motors when you don't have quite enough amps to do the job. But like stated before and I have to force myself to listen. these machines were not meant to be thrown in reverse like a modern machine. Kerry (10836)
SB 9 motor
I would appreciate info on a replacement motor for my lathe. I know there have been several postings on this subject but would like to get confirmation on the right spec for the motor. I understand that the motor should be 1725 RPM, but if not reversible, is rotation CW or CCW? Should the HP be 1/2 or is a larger HP better? Also, what should the amp rating be for the motor when operating? I would also like to get confirmation that the frame size is 56. Barry (10875)
Measure twice, order once. there are lots of places on the web that give exact motor dimensions. better to measure what you have than get what someone else tells you to. reversible will be available, so don't consider one that is not. 1/2 is the original spec and the imports supply a 'Chinese' 3/4 hp. if it anything like the 'Chinese 1/3' hp motors on my drill press, it really would be a tad under 1/2 hp. more motor and you can break things. Check for local suppliers, Grainger sells them so you can always order. Dave (10876)
Here is the data from the nameplate on mine; It had been replaced ~15 years ago: The direct replacement is a (Grainger's) Dayton #4K 781R, Capacitor AC Motor, 1/2 HP, ball-bearing reversible motor that can be jumped for 115 or 208-230 VAC 60 Hz, 9.6 Amp full load @115, 4,5-4.6 A @115-230 Frame 56, SF 1.0 That stock number may be old, but I searched their site and found a couple that are similar, as well as an equivalent at MSC Online. (10877)
Barry, In my 9A (original factory all the way) G.E 1725 RPM, 1/2 HP, 50 deg rise. Normal (forward) rotation CW). RichD(10883)
I would like to know something, I have a couple of reversible AC motors laying around the shop. I have never reversed one however. Would this work OK with just a forward reverse switch? or once wired for a particular direction that is it unless it is rewired again? can someone shed a little light on this for me? Clint (10890)
Clint, Most reversible motors require that the field wires be reversed on the terminals under the cover plate on the bell housing. If you bring out leads from the terminals and extend the wires to the field windings, you can hook up a DPDT motor rated toggle switch to allow reversing. If you can find a drum switch in the correct configuration, or a 3PDT switch, power can also be controlled by the same switch. If not, you end up with a direction switch and a power switch. If you pull the wiring cover panel from one of the motors, the connection instructions are usually pasted to the inside of the cover panel. Holding the switch with the terminals up, with the three terminals at each side, the terminal lugs connect to the two center terminals The field winding leads go to the two terminals on the top or bottom, doesn't matter. The top right terminal gets wired to the bottom left terminal, and the top left terminal gets wired to the bottom right terminal. If you use short wires for the top right to bottom left, top left to bottom right deal you end up with a wire "X" with the crossover between the two center terminals. Probably easier with a picture, but I'm pretty poor at creating understandable ASCII art. Stan (10891)
Clint, Some reversible motors are easier to wire-up to a reversing switch than others. Most later motors use the NEMA wiring standards and have separate wire leads that are numbered (like T1, ... , T5, T8). These are the easiest to explain and IMHO, the easiest to wire to a reversing switch. Leads T5 and T8 are used to determine rotation of the motor. If yours is this kind, there is (or at least should be) a connection diagram or chart showing how the leads are connected. This should be either on the motor I.D. tag or under the cover plate that allows access the leads. Older motors may use color coded leads or have a circuit board that you connect leads to and/or has "jumpers" or "shorting bars" to make internal connections. The latter are the more difficult (but not impossible) to wire to a reversing or "drum" switch. If yours has the circuit board arrangement, you will need to identify leads and probably have to cut and splice new leads into the motor in order to get it to be reversible from a drum switch (bypassing or eliminating the circuit board completely). This is not too difficult to do but you need to understand how a single phase electric motor works and how it starts. Also an Ohm meter is an essential tool in this kind of work. Before going on any further, I recommend that only capacitor start motors be used on machine tools (that is, instead of a plain old split phase motor). They have more starting torque. (Yeah, I know; repulsion start motors have excellent starting torque and would be good for machine tools too but they are not very common). Also, the motor should be rated for continuous duty. And a service factor greater than 1.0 is nice too but not necessary. If you have a reversible continuous duty capacitor start motor with separate leads, then you are in business! If you know what leads your motor has and the type of drum switch, post them and someone here should be able to tell you how to wire it up. Webb (10892)
Stan and Webb, this help a lot, I think that I can figure it out. I will go thru some of my old motors and see what I do have. Once I get some more info I may need to call on you guys again I will keep these two postings handy. Clint (10893)
I had a 1.5HP motor on my 9" junior. Worked fine just the motor itself was real loud so I put on a 1HP and it works fine too and not loud. 1HP I would say is the max on a 9" I've got mine running with a larger motor pulley to get a top speed of 1000RPM. Now I don't use the top end much but it nice to have for the few times I've needed it. But I do watch the temp of my bearings when I run it that fast and I don't leave it running to answer the phone. There's a reason they designed it to run at 650 rpm. so I don't want to push my luck. Kerry (10913)
DC Motor conversion
People have asked me for wiring diagrams. A good set comes in the manual for the controller I bought from Graingers. The wiring of the 4PdT switch for reversing rotation and turning on the AC can be found at: http://www.dartcontrols.com/InternetConfig/Manuals/125DManual.pdf The general scheme is valid for any full wave SCR controller. (11879)
I just received a copy of the Dart Control Instruction for the 125D control. What page references the hook-up I should use and how do I insert the ammeter? Bob (11911)
I just received a copy of the Dart Control Instruction for the 125D control. What page references the hook-up I should use and how do I insert the ammeter? I found the ammeter is only a frill. I put mine in series with the AC line because I happened to have an AC Ammeter around. If you do that I suggest a 10 amp meter. An DC Ammeter on the armature side should be 6 amps full scale for a 1/2HP motor and 8 Amps for a 3/4 HP. BTW, there are some great 3/4 HP controllers on E-Bay that are much better than the new $70 ones from Grainger's, and going for about $50. They have adjustable acceleration. The new Darts from Grainger's are set at 6 seconds to full speed, something I found annoying. The KB Penta Powers on E-bay require a calibration resistor, about $1 or $2 from Allied, depending on the size motor you use. I got a 3/4 and am using that as it gives a comfort factor for torque. (Also from EBay.) The KB units will run 3/4 HP with NO ADDITIONAL HEAT SINK! The Grainger's Dart controls want an additional heat sink. The top of Page 9 in the Dart manual shows the wiring for the 4PDT switch. This is common to any such control. (11914)
Lathe motor base/mount
Are there standard bases for motors? I replaced the motor on my 10k and bought a new AC 1/2 hp from a local dealer and it fit perfectly, but he knew where it was ging. How can one tell if a motor will fit existing mounting holes? Frank (12812)
Most fractional HP motors are made with standard bases or mounts. There are several types, but most of the motors for small machine tools use the "56 frame" mount. RichD (12814)
S/B Motor size
I have a s/b 10 x 36 it now has a 2hp 3phase motor in it what size motor did these lathe come with it seems to me that this motor mite be a little large for this lathe please help. JIM (13043)
I restored mine with a NOS motor from Dayton, it must of sat on a shelf for 20 years... it's so perfect. I think it was a 64c frame if I remember, I think that was the replacement motor, I know the Horse rating is a little more than what was on the original 3 phase one, which is generally a good idea. If I had my original 3 phase, I would have given to you, but I think it went to the scrap yard. Jason (13044)
I'm not sure what frame it was actually, and I can't read the stamping underneath... it was either a 46, 48, or 64 type, probably one or two of those aren't real motor sizes. Jason (13045)
If you are talking heavy 10, the stock motor on mine was 3/4 hp (1953 vintage) The bimetal strip capacitor switch burnt up so I ended up replacing the motor with a 1HP. John (13064)
Motor recommendations needed
I'm looking to replace my motor on my SB 13" with a single phase unit. I'd like to continue to have "reversibility" like I had with the 3ph unit. Have any of you done this? Pitfalls? Recommended motor types and sources? (13077)
If the 3 phase motor you have works fine, consider getting an Inverter (VFD). You can run it off single phase 220, make it variable speed, etc for less than the price of a new motor. I do this with my Bridgeport and it works like a charm. John (13078)
Michael, Try looking for motors at http://www.northerntool.com/catalog/ I bought a 5hp 1ph 184T frame Marathon motor from them and it was cheaper than any I could find locally. It runs my air compressor and has been very reliable. (13080)
I bought a 1.5 HP single-phase GE motor (P/N 5KCR49SN0065A) from Grainger for my 13". I had to make an adapter plate because the NEMA mounting from the original motor was obsolete. (13090)
Do you remember what size the obsolete NEMA plate was on your lathe? I found a NOS Dayton motor luckily, but I can't for the life of me remember what frame it is, and I can't see under the drive to read it. I keep saying it's a 64c frame. or 48c frame... The thing is, the C series frame available now are something called skeleton frames. I don't think the original 3 phase Westinghouse on my 10L was a skeleton type. Jason (13091)
Grainger for from the original funny picture. it's not real ! no rust, no grease, no leaking oil stains and no chips! (13119)
Motor - Single or 3-phase?
I have a 13" South Bend that I picked up, but do not know if the motor is single or three phase. The plug on it is a configuration I do not recognize, but the wires from the plug to the drum switch are the standard white/black/green. I did hook up the wires to a 220v outlet (single phase) and the motor appears to run fine. I do not have the belt for it right now so I do not know how it will run under load. After this experiment I would assume it is a single phase motor, but is it possible I have only energized one set of the windings in the motor and it just happens to run? The motor starts right up like electric motors usually do - there is no hesitation. According to the data sheet from South Bend it shipped with a three phase motor, but that doesn't mean it wasn't replaced. I can't find a data plate on the motor. Alex (13196)
How many wires does it have coming from the motor, normally the 3 phase will have 9, some have a different number, but this is my understanding of in general Since it started right up OK, I would assume it is single phase. Clint (13198)
1. there should be a printed or embossed nameplate riveted on the motor - this will tell you what the electrical characteristics are 2. look inside the motor terminal box - there may be a label showing the wiring and characteristics. 3. find the motor brand name and any data on any identification plates and we can help look up the data from that if it is a 110 V motor it may start and appear to run fine under no load on 220 but may very quickly overheat and burn up. induction motors derive their rotational speed from the speed of the system ( 60 Hz) and not the voltage so it would turn at nearly the same speed as if it were on the correct voltage. if it was a 220 plug - it was most likely a standard type item and can be identified - many plugs are made specific to the voltage they are intended to carry so that people don't plug them into something inappropriate. take a picture of the plug and post it so we can identify it. be aware that if you are dealing with electricity, you are handling a lethal dose of energy. it is NOT safe to experiment with it and you may be risking serious injury if you do not have the proper safety equipment and training. but the white/black/green. (13203)
Alex, Sure sounds like a single phase motor to me. Three phase motors typically have 4 (or more for some configurations) wires, and don't usually start if they have just a single phase applied. If the green wire is ground it's certainly single phase. If you have an ohmmeter, just check for continuity from white to black and verify neither of these leads has continuity to green. Stan (13204)
I did finally find the data plate it was very well hidden under the box where the wire connections are on the motor. Even harder to see since the motor is so close to the ground. 1 HP Single phase. Thanks fo everyones input, Alex I'll post some pics when I am done with the restoration. (13220)
Problems starting lathe
I've just about finished my rebuild of my heavy 10" but I'm having problems getting the lathe to turn over. I have the old pedestal type with and if I have selector that powers the leadscrew and drive train in neutral the lathe will turn over but the motor has to come up to speed or sometimes I have to grab the chuck and give it a little push to get the lathe to turn over. If I engage the level to power the gear train the lathe wont turn over at all. If I remove the gear that is connected to the lead screw at the quick change gear box, the lathe still has problems turning over. I can turn the gear that is attached to the lead screw by hand while it's connected to the gear train. Any ideas as to what is wrong? I've left the quick change selector out of gear so I'm not trying to power the quick change but still it won't turn over. When it is on and not turning, I don't see any belt slippage either on the motor to pulley that is attached to the lower 3 step pull or the leather belt that goes between the two 3 step pulleys. Is it possible that the motor is burned up or since it's a two speed 3 phase motor, is it possible the starters are bad? I apologize for my lack of terminology but I don't have the repair book with me at the moment. Terry (13382)
Check the fuses first, you could be trying to run it in a single phase condition. Look for three phase at the line side of the starters. A-B B-C and C-A should all have line voltage. Make sure the motor is connected for the voltage you are using. Those are two things that will cause a three phase motor to fail on start, even though it will run with no load ,if you give it a push. I worked on a Sheldon that was connected for 460 volt operation last spring and the labeling tags were under the tape. Until I unwrapped the tape I thought the leads were un-labeled. Changing it to 230 volt operation became an easy task when I discovered the labels. My point is don't lose track of the labeling on those motor leads, a dual voltage motor has a lot of coils. RC (13384)
Terry, When the spindle is not turning, and you say you do not see any slippage, is the motor still turning or does it quit? in other words, when it quits turning, does the motor stop also? or does the motor turn and the spindle stops? Have you got 3 phase power or a static converter? Clint (13385)
With the gear train in neutral and if I turn the power on the lathe will power up to speed. I then turn it off wait for the head to stop and engage the valve train either forward or reverse. Turn power on and nothing moves. When I look at the motor the shaft is not turning that powers the v-belt pulley to the large 2 step pulley that is on the same axle as the lower 3 step pulley. If I give it a push, then the motor will turn over and the lathe will come up to speed. If I have the quick change gear box engaged then I can't even turn it over by hand, so I'm not ruling out that I messed something up in the quick change. I have true 3 phase power at the shop at 220 volts but I need to double check that the motor is not setup for 440. Also, when the gear train is running, it's pretty loud. Not making a grinding noise or anything just noisy. I'm hoping that since these are straight cut gears and not meshed that the gear train is just going to be noisy when running. I've taken apart the selector off the head stock and broke it apart to clean the 2 small gears and the larger 2 gears that are on the bearing that fits inside the headstock. I felt that it was a little tough to turn over so I took it apart and cleaned all the surfaces and replaced the felt. Now it turns better and doesn't make as much noise as before but its still noisy. Terry (13386)
Terry I think you need to check out the hook up like was suggested by another post. I do not think the problem is with the lathe, just either the motor or the wiring. Clint (13387)
Well it turns out that my motor is a 440v 3 phase but my shop only has 220v 3phase. So can these motors be converted from 440v to 220v or do I need to buy a new motor? (13407)
You should be able to get the motor rewound at a motor repair shop. I had a 3hp 575v/3ph motor for my milling machine rewound to 220v/3ph for $250 or so locally. (Boston area). However, if your motor is a standard frame type, you'd probably be much better off just buying a new motor - you can probably get one for half the price of the rewind, or less! You could also get a step transformer on eBay for around $50-75 that would do what you want to do. C.S. (13408)
I had a similar problem with an Oliver lathe motor, and my local motor repair guy was able to rewire without any fuss. He did say that the wires had their original metal tags, which made it much quicker, since he didn't have to track anything down. It cost me $20. Bob (13409)
Terry Somewhere there should be a plate showing a wiring diagram of 220/440V I think some 3 phase motors could be only 440V, but doubtful this is your case?? since it was with the lathe?? Have you pulled the cover off the wiring box on the motor and see if it is on the back side of the cover? Clint (13411)
If you go with another motor, you can pick up 3 phase 220V motors for a little of nothing try this place http://www.surpluscenter.com How many wires have you got going into the motor? 9?? are they numbered? Clint (13412)
If it is a 9 wire and still has the tag numbers, I can tell you how to wire it. Clint (13413)
I went over to the shop and looked but the wiring cover on the motor doesn't have a wiring diagram, unless it's inside the housing. But the way that I have the motor hooked up is the following: Wires 1, 2, 3, 12, 13 come from the switch. Inside the wiring cover I have these wired to wires T1, T2, T3, T11, T12, T13 in the following way. 1 - T1 - T11 2 - T2 3 - T3 12 - T12 13 - T13 The information of the plaque on the motor doesn't describe the motor as a 220/440v just a 440v. Model 11558M45 Type COGMX Volts 440 Freq 60hz HP 1 Frame 184 Speeds 1710 rpm / 820 rpm. Terry (13414)
Terry I am afraid to tell you that apparently it is for 440 only, now if there is a way to go with 220 I do not know how but sure it can be done. What you will find however, is you can add any motor cheaper than messing with rewiring, etc, on that motor. Motors are just to cheap now days and easy to find, especially at auctions, but you can find new ones under a 100.00 All you need is a 110 V, 220 V 1/2 HP motor, or a 3 ph 220V 1/2 HP If you find used ones, do not worry about the exact HP, you can get by with 1/3 to 1 1/2 HP motors and any of them will work fine with your lathe, just make sure it turns the correct direction. You can even run a washing machine or dryer motor but do not recommend the open housing type,, the chips can get inside and short them out. OH, make sure it is close to 1750 RPM and not 3450 If you were close to me, I have several motors just laying around. Clint (13415)
I would go with a single phase motor on a 9" lathe. That would allow you to get rid of that starter, and just use a drum switch, if you want reversing, or a toggle switch if you don't. The main advantage is the increase in resale value of the machine. Like Clint says the little lathe just doesn't have need of brutal power. Nothing is more convenient than a 120 volt single phase machine. RC (13416)
I just looked at your members profile and it says you are in N Texas. I'm in DFW and don't mind driving. I would be interested in swapping if you want. Terry (13417)
I am in Austin and have a lot of experience with electrical and motors. I make my own three phase converters, and do a lot of industrial electrical, if I can be of some assistance please contact me. Mike (13418)
Terry I do not need the 440 V motor, but let me look at a 110 V if that is OK, I will let you have one. If you decide later that you want a different one then it would not be that hard to change out again But we can find something here to get you going I am up North Of Celina, do you know where that is? Clint (13439)
Terry I forgot to mention, if you bring your 3 phase motor, we can also take a look at it and make sure that it can be wired for 220, if so we can test run it with my 3 ph converter Keep in mind when visiting, my shop looks like a work shop! Clint (13440)
Mike Thanks, I am sure plenty of us will need your advice Clint (13441)
Terry Was you able to get the motor mounted and tried out today? Clint (13577)
3 phase?
Will a 3 phase motor run if given a preliminary spin with a starter rope and then plugged into single phase 220 on 2 of the 3 legs of the 3 phase leads leaving the third leg unwired? What about rotation or will it run in direction of spin? This is only for a little test if it can be done. stirboy (13580)
Bill, Yes, it will run, in the direction you spin it, just as you say. To make it self starting add a motor starting capacitor in series with a push button switch, the 3rd leg then to either of the other 2 legs (test for direction). Adding run capacitors will make it more efficient. Now you have a rotary convertor or a way to use that 3 phase motor on 1PH on your mach. tool. Adding a NC relay in place of the switch will make it automatic. Not all, mostly modern motors, will work this well, but try it. RichD (13584)
That's a fine way to test a motor. You don't have to spin the motor very fast. I have used a piece of nylon twine with about 10 turns around a 1" shaft. You don't have to spin very fast; the faster it's spinning the lower the starting surge. Starting an unloaded 7.5HP motor on a 15A 220 V circuit this way will trip the breaker now and then. Keith (13585)
Stirboy Yes they can, but no power. With no load they will run, or at least some of them will. They can also get hot and burn up. Clint (13587)
Power King motor
Anyone out there running a Power King single phase motor, on their SB 9"? My 9A came with a Power King 1/3 HP, 6 amp, 1725 rpm, 1 cycle motor - made by Power King Tool Co, Warsaw, IN serial # 252260 I haven't used the motor yet, as I haven't gotten around to cleaning up my lathe - I got it mid-summer. I was just wondering if Power King is a good motor? Who knows, the thing might not even work. I will have to give it a test one of these weekends. W. Sharp (13878)
I haven't heard of that brand, but my 9A is powered by a 3/4 HP. 1/3 HP might be a bit small. I can't find the recommended size in HTRAL either, but 3/4 hp seems to be enough. W. Sharp (13987)
Yes they were good motors, I don't believe they are made anymore. If it works and doesn't smell when it runs use it. The older motors had a lot of inertia to them and the performance of a 1/3 hp old motor is better than a 'new' one of the same rating. If you replace it then go bigger. My 10" came with a 3/4hp 3phase and I replaced it with a new 1hp Leeson motor I picked up on Ebay for $50. Frame sizes have been consistent for a long time so the mounting of a new motor should be relatively simple. JP(13989)
JP, Thanks for the input on my Power King post. When I get a chance, I'll wire it up and she if she run? Bill (14027)
Electric Motor Frame Sizes
Would anyone on any of these groups have access to an Electric Motor Frame Designation Book? I have a Gray-Mills Coolant Pump on my Bridgeport Mill and would like to change the motor from a 3 Phase to a Single phase motor. I have been told by local Motor Rewind Shop that this motor is of proprietary dimensions in flange mounting size and bolt pattern and he would have to order direct from pump manufacturer. I would like to know if he is just trying to drum up some expensive business. I have been to manufacturer's web site but do not see my style of pump which could be 30 Yrs old. Anyway I will give pump dimensions and if anyone can let me know if this is standard motor and what frame style it is I would appreciate it. BTW there is no frame style info on pump tag. Pump is 1/8 HP and has an end housing on it where it will sit on pump housing of 5.500". This end housing also has a spigot on it 3.000" Diameter by .150 High. Motor is bolted on to pump housing by four 1/4" bolts on a 3.750 Bolt Circle. Motor shaft size is unknown at this time as I have yet to get extension shaft coupling off but is really unimportant as I can make an adapter to suit motor shaft and extension shaft. Ron (16263)
Ron, I'm not sure how much this will help, but try going to Grainger's web site at http://www.grainger.com to try to figure out your motor. Dave (16265)
Ron, Are you sure you want to bother with this? I don't think most of us use coolant in home shops. Ed (16266)
Ed: POSITIVE Ron (16267)
I have a Gray-Mills Coolant Pump on my Bridgeport Mill and would like to change the motor from a 3 Phase to a Single phase motor. I have been told by local Motor Rewind Shop that this motor is of proprietary dimensions in flange mounting size and bolt pattern and he would have to order direct from pump manufacturer. I would like to know if he is just trying to drum up some expensive business. I have been to manufacturer's web site but do not see my style of pump which could be 30 Yrs old. Anyway I will give pump dimensions and if anyone can let me know if this is standard motor and what frame style it is I would appreciate it. BTW there is no frame style info on pump tag. Pump is 1/8 HP and has an end housing on it where it will sit on pump housing of 5.500". This end housing also has a spigot on it 3.000" Diameter by .150 High. Motor is bolted on to pump housing by four 1/4" bolts on a 3.750 Bolt Circle. Motor shaft size is unknown at this time as I have yet to get extension shaft coupling off but is really unimportant as I can make an adapter to suit motor shaft and extension shaft. (16268)
Motor size limit for 11" lathe
I have an 11" 1 3/8" spindle Logan (put together from several different Logan's) that is currently using a 3/4 HP 110V motor. My hose has single phase 220 juice in the basement and I have a 1 HP 3 phase motor and a 2 HP 3 phase motor... I was thinking about using the 1 HP on the Logan and using the 2 HP in a 3-phase rotary converter. Is a 1 HP 220V 3 phase motor too big for my Logan? I know a 3 phase motor develops more equivalent power than a one phase so technically all I would need would be a 1/2 HP 3PH to replace the 3/4HP 1PH 110 V. motor. The question is will I cause any problems using a 1 HP motor? Because I have it around and all. Kiira (16342)
Here's my take on the question: Look at the original equipment specifications on the South Bend Co. website. For the 13" Series O lathe, they show the original equipment motor size as 3/4 HP. Further down, they say that a 13" Series O can reduce the diameter of a steel shaft by 5/8ths of an inch in a single pass. (Presumably, this is some kind of very easy- machining steel, cause that implies raising a 5/16ths" chip! Sheesh!) With that in mind, 3/4 HP ought to be OK for an 11" lathe, assuming comparable belt drive and gearing. There's a downside to excess power. Suppose you have an accident? Like running a chuck jaw into something, or running the carriage into the head- or tailstock in power feed. Accidents do happen. In such a situation, the less HP you have, the better!!! While we're on the subject of safety, make sure you have a reasonably- rated circuit breaker or fuses protecting each of your machines! Obviously, this is only an opinion based on the facts outlined above. John (16348)
16" motor horsepower
My Father in law and myself have been working on a ~1942 16" swing 8' bed (117-E). We have almost completed scraping, painting cleaning oiling etc. The original motor was not with the machine when we bought it. Does anyone know what horsepower the original motor would have been on a 16" swing machine? The original vbelt pulley on that motor was also missing, but I calculated the spindle speeds with various pulleys and it looks like a 4" will be right. (16363)
My 1960 SBL catalog lists 2 hp @$223.00for 3 phase use and 1.5 hp @$316.00 for single phase use. Wayne (16463)
I imagine that by this date it would be a 4 step pulley machine which frequently used a two speed motor. Even if you don't bother with a two speeder (expensive) its well worth fitting extra pulleys to give two speeds as the speed range is much more useful. The top speeds in High and Low range are 980 and 470 whilst the single speed version checks out at 490. A slow lathe can be a right pain for some work. If I were setting up I'd be inclined to pick pulleys for 900 and 250 or 300 top speeds in the high and low range, having some slow direct drive speeds for big jobs can be very relaxing on a big belt drive lathe. Watching a decent cut come off a big job with the chuck marching round in stately near silence is just soo nice. Another big pulley for the countershaft can come expensive. Either wait until you have things going and make one or add an extra shaft so you can use some smaller, cheaper pulleys. I find the bearing units out of scrap spin driers excellent for this type of extra shaft job. Clive (16464)
I too, have a 16 inch SBL. It came with the original 3 ph motor which I still use along with a motor controller (no loss of power). It is 1.5 Hp. Philip (16479)
The motor we were planning on putting on for now is a 1.5hp. I was pretty sure it would do well enough but I am happy to see that it was deemed sufficient on original equipment. The motor we have has only 1 speed, but I have a reasonably large pulley which will give me a rather high top speed ~1500 rpm that may or may not be useful, the lowest of the low, if my calculations are right, would be about 45 rpm in back gears. so the range of speed should be good enough for most jobs we tackle. (16481)
Maximum Power for Heavy 10?
What is the maximum HP motor that the Heavy 10 can safely handle? When these machines were driven by overhead belts in a large shop there must have been a great deal of power and momentum available from the main lineshaft. I don't want to overpower the lathe but I'm a little disappointed in the current performance I'm getting with an old 3/4 HP motor. (17638)
When I first got my heavy ten I took the 3 phase 3/4 hp motor to a rebuilder and recommended replacing it with a 1 hp motor being it was soooo beefy. It has been doing a good job for twenty some years now. Joe R (17643)
New motor HP and RPM maximum
I've got a '33 SB 11" underdrive lathe that's working fine. I have been thinking about upgrading its 1/2HP motor with something more powerful (maybe 1 HP) and capable of providing higher spindle speeds. I realize there are likely bottle necks in the lathe's drive line (belt, bushings and gearbox?) and I'm wondering how severe they are. Any rules of thumb about max power and spindle RPM a lathe like this can accept without trashing its (presumably bronze) bushings? Can I raise HP and keep the RPM the same or visa versa? Peter (18398)
I use a 1hp 1725 rpm on my 10" and it works fine. It came with a 3/4hp. I wouldn't use a faster motor, just sharpen your HSS bits and trash the brazed carbide offshore junk. JP (18399)
I've got an 1150 RPM motor on my lathe now. What type of spindle RPMs are you turning? Peter (18401)
What is listed in the HTRAL book. You can resize the motor pulley to match the rpm, go to 2/3 your current motor pulley pitch diameter when switching from an 1150 rpm to 1725 rpm motor. My RPMs are 1357, 837, 535, 700, 434, 277, 129, 79 and 50. The change in hp from 1/2 to 1hp will make a big difference. JP (18408)
SB 9 replacement motor help
My SB 9" has a Century A66 motor set up for 480v and I would like to find a replacement motor that I can run on 110 volts. The A66 motor doesn't appear on any NEMA motor charts I could find. Does anyone know of a suitable replacement motor and its frame #? I posted the same question a few weeks ago and nobody responded, although there were bunch of interesting (and helpful) threads going on at the time. Tj (18870)
Undermount or horizontal drive? 1/2 HP is plenty big for these lathes. You need to measure the mounting bolt patterns. Then look at a reference like a Grainger book for frame info. http://www.grainger.com/Grainger/static.jsp?page=resourcecenter.html http://www.grainger.com/Grainger/static.jsp?page=rc_nemafmgd.html dennis (18872)
Dennis, Horizontal drive I didn't mention that in the previous post. Tom (18873)
Tom- And once you find the price on the one in Grainger, contact me and I have one you can have for 1/2 of that. Jeff (18874)
You can run virtually any common 1/2 or 1/3 hp 110 volt motor on a 9".. The backdrive frame is very adaptable to any motor.. I don't bother with all the NEMA frame data. If it has a frame with 4 holes it will fit. Personally I only buy garage sale motors for all my stuff, never paying more than about 10.00. I have used such a high end motor on my 9" for about 4 years with no problems. When I dies I have a similar replacement ready to go. (18875)
I just bought a 3/4 HP motor from Northern Hydraulics to put on mine. Cost about 100 bucks and change. The shaft size requires a bushing and the base plate requires some drilling and tapping. You may or may not find one that matches the shaft and footprint of the old one exactly. Probably cost you double the hundred buck number though. (18876)
I like your method, but I have some questions. Are all motors reversible? Is this accomplished by altering the wiring? I'm asking because I have a 3 phase motor presently, and want to exchange it for something I can run on regular house current. How about a wiring diagram? John (18878)
Go here for diagrams http://shop.emotorstore.com/estore/TD_Schematic_Diagrams.asp? Many motors, but not all, are reversible. I bought a 2 HP capacitor start compressor motor from HF. It stated "Not reversible". This is seldom true. Your typical house current motor must come to a complete stop before it can be reversed. These motors have a starting winding. This winding determines the direction of rotation. Once the motor starts, the winding is disconnected by a switch (centrifugal). The motor runs on the run winding. Changing the direction of the motor requires re-connecting the start winding. This can be done with the same switch you have on the 3 phase motor. However you must allow the motor to stop before reversing it. This however is very good practice. It reduces strain on the lathe and stops threaded chucks from spinning off and rolling across the floor. Jim B. (18883)
9 in Motor Selection
I recently received a 1953 9 inch swing model A lathe and found the old motor to be full of steel chips and falling apart with corrosion. This lathe is a horizontal motor drive. I also have the 9 terminal cutler-hammer drum switch that came with it, this is in great condition. I would like to be able to wire it to the switch so the spindle will go in reverse, unlike it is currently wired and the way my heavy ten is wired. What type of motor would you recommend? Henry (19931)
I bought from Grainger when I needed a new motor for mine. 1/2 hp is recommended for the 9". Anything more is kind of a waste of power. Anything the lathe was designed for can be accomplished with 1/2 hp. Make sure you get the motor with full duty cycle, reversing, sealed for machine tools. Paul (19934)
This subject keeps coming up. There are as many answers as there are SB-9 owners. 1100 to 1750 RPM, (as low as 1/3) but generally 1/2 to 3/4 (perhaps a full 1) HP. If you want to get fancy get either a 3 Phase motor and a phase converter or a VFD. Some owners like DC motors with speed controls. Keep looking in the thrash buckets. a lot of washing machine/dryer motor turn up there for free. The washing machine motors are usually two speed. sometimes an advantage. DC motors can be found on defunct thread mills along with controllers. Its all a matter of what you want and how much you want to spend. The one on my lathe was scrapped, it had a noisy bearing. 23 years later it still has the same bearing. Remember that a capacitor start motor must come to a full stop before it can be reversed. A 3 phase or a DC motor can be reversed without stopping. Consider that this WILL put additional strain on your lathe and that the chuck can EASILY spin off and cause considerable damage not only to the lathe but to the operator. Also consider why you feel the need to reverse the motor. It is of use when threading, to be able to run the tool back to the starting point without disengaging the leadscrew. It is of use to put a tool on the far side of the cross feed, although putting an upside-down tool there is pretty much equivalent. It should not be used for a "quick stop". Jim B. (19935)
With 9 so the 1/2 HP capacitor start motor. 110v (19943)
Cleaning out my files last night, I came across a 1956 SB lathe catalogue in mint condit. They shipped these originally with 1/2 horse. They put 1/2 horse on the 10k as well and that's what I did when I put a new motor on mine, but I am sorry now that I didn't go 3/4. I would advise the 3/4, even though the 1/2 is perfectly adequate. It just lacks a little "oomph" Frank (19950)
I keep hearing rumor that an olde-tyme horsepower and a modern one for electric motors are different, the olde-tyme one being a somewhat stronger horse. Then I hear that, No, that's false, but the olde-tyme motors tended to have heavier windings, modern ones being closer to the "bleeding edge". Bottom line is that where Grandpa used a 1/4 horse in 1929, we use a 1/3 now, and so on up the line for fractional HP motors. So subbing a 3/4 for an "olde" 1/2 makes sense. I've got a modern 1/2 on my 9" now, and a 3/4 over in the corner in case the 1/2 proves weak. All rumors, of course. Dave (19959)
[snip] When I took the 3/4 HP 3 phase off my 40's vintage 10k to the motor shop to get a new single phase one, without seeing it he said a 3/4 would be fine. After seeing it he said "you need a 1 HP". Joe (20007)
Heavy 10 motor replacement
I have recently acquired a SB heavy 10 complete with taper attachment. The lathe came with a 3 phase 1 hp motor which I will replace with a single phase motor. I have a 1 hp motor with bronze bearings however the oil caps would be on the bottom since the motor mounts upside down. I also have a ? hp motor with ball bearings. What are your thoughts on using a ? hp motor on the heavy 10 for hobby use? The current draw would be a little less and I am not doing production machining where I need speed so I can take smaller cuts. Both motors are reversible. So would you use the 1 hp or the ?. Ray (20239)
For hobby use, 3/4 HP will work fine. As to the oil holes, you may be able to unbolt the end bells from the motor and turn them over (I mean rotate 180 deg.). You will have to check that the wiring will permit it but usually you can do this. Webb (20248)
Webb, I did look into rotating the end bells but the wires are not long enough so I would have to splice extensions onto them. That operation may injure the 30+ year old insulation so I hesitate to do it. Also the ? hp is a TEFC motor so it is chip proof. Ray (20254)
Ray Years ago I dealt with a similar oil cup problem by welding up a new U shaped bracket to hold the motor via the long studs which hold the end covers onto the central core. I had to replace the standard studs with longer ones (use screwed rod of suitable size from wherever you can get it) so that the nuts would screw on properly. I think I used 1/8 or 3/16 steel sheet for the bracket. Sure looked funny having the motor with its feet up in the air but it worked fine for several years until I sold the lathe. Naturally this was a 3/4 horse single phase with the oil cups arranged for hanging down operation which I wanted to use the usual way up. Another possibility which just occurred to me is to mount the motor on a flat plate big enough to run long columns up past the side of the motor and fix those onto the mounting bracket. Given that it can be a right faffle getting at the back bolts when fitting the motor doing it this way might be easier 'cos you could fit the columns first and offer the motor up afterwards so all the nuts are underneath where you can get at them. Even simpler would be a pair of flat, U shape, straps with the tops bent over. Bent over tops bolt to the mount, long bottom sides go under the motor feet. Probably easiest to get in with the strap bases running along the motor rather than across. Need to be pretty hefty material to stop it flopping about tho', 1" x 1/4" at least I'd guess. Clive (20262)
Ray, When you had the end bells off, did you check to see if the starting switch could be unbolted from the end bell and reattached after rotating the end bell? Some of these starting switches can reversed. Alternatively, you could just replace the insulated wires completely. It isn't that hard. You just have to trace each insulated wire back to its connection on the coils (or capacitor) and cut them off and solder a new lead on. There are stick on numbered labels used by electricians that can be used to keep the numbering on leads straight. Lastly, if you can rotate the end bells 90 Deg.s, so that the oil holes are pointed out to the side, you could fit some Gits elbow oilers. Gits makes elbow oilers in many size and in both threaded and press-in mountings. Webb (20280)
Webb, This motor has a thermal breaker across from the starter switch so the casting is not symmetrical, but it’s a mute point now. I installed the ? hp totally enclosed motor and it is working great. I faced and turned an old adapter plate to fit a 6” 3 jaw I picked up and am about to drill and tap the three holes to bolt the adapter plate to the backing plate. The adapter plate, which threads onto my spindle, has 3 5/16-18 holes but I think I will change them to 3/8-16. I am debating whether to drill and counter bore the backing plate for the cap-screw heads or just tap the backing plate and let the heads stick out behind the adapter plate. Ray (20297)
Motor Choice for 13" SB?
I've got this 13" I'm tearing down, fixing, repainting, etc. and it came with two motors. The one that was mounted and running it is a Chinese 1 hp, single-phase, 1725 rpm. It also came with a good Leeson 2 hp, 1725 rpm, three-phase. The SB data sheets for this lathe say it came originally with a 1 hp motor. After reading some other posts about how older motors were actually stronger than newer ones, especially the Pacific Rim imports, I'm wondering if I'd be better off mounting the 2 hp Leeson and building a static phase converter and getting maybe a real 1.3 hp out of it than using the Chinese 1 hp and maybe getting something less than that. Also, the Leeson is TEFC and the Chinese is ODP so the Leeson is chip oil-proof. I'm not really interested in a VFD and I can build a phase converter easily. Power supplies/wiring, etc. is no problem. When I built my shop, I over-designed all wiring, panels, breakers and can easily run 220V or heavy-duty 115V to anything. BTW, I've used the same static phase converter on my Millrite vertical mill for over 15 years without any problems whatsoever. So, the question is - is going to the Leeson worth the extra time and money? Ed (20270)
No brainer, go for the Leeson. Lots of Chinese motors are sold rated on the input power consumption converted to hp and are very inefficient designs as well. Some of the cheaper 2800 rpm ones will barely deliver half the rated power and will stall out if you look at them. If you haven't got the specification leaflet you won't know. Last time I was conned the leaflet said 3 hp input, 2 hp output and the output horses were pretty small too. In general older motor designs have much better torque overload recovery than modern ones so they don't stall out so easily making them seem much stronger especially on loads where power needed falls off faster than revs. This characteristic is basically dependent on the diameter of the squirrel cage rotor, bigger is huskier. Older motors tend to be larger in diameter than modern ones hence the reputation for being stronger. Flip side is that motor efficiency is higher for smaller cages. Modern motors tend to be designed for best power consumption at the rated load. Small and modern could easily be using 10% less electrickery than big old. Clive (20271)
I have a 13" with the original motor and static phase converter. Unless you are going to turn anything that will use a lot of power (4" Dia 5 foot long tube) or something that requires a lot of torque, you will not miss it. (20276)
Heavy 10 Motor Change?
I just bought a 1975 Heavy 10 with an underneath motor drive on a cabinet. The motor requires a 208v, 3 phase supply. I've been told that I can buy an electronic phase converter to supply the 3 phases, but I'm wondering if the 208v is a problem or not. Would it be simpler and cheaper to change out the motor to one requiring 110v or 220v single phase? I can supply either 110v or 220v. Is there a reason to go with one or the other? Also, are there rpm issues that must be considered? (20485)
Look in the box that supplies electrical to your air conditioner. If it has 3 fuses or a place for a third fuse, you have 3 phase. If so, compare the cost of running a line from there to your lathe vs. a phase converter vs. the cost of a motor. If you plan to add any additional 3 phase equipment such as a mill, 3 phase would be great. You should read the earlier posts concerning Variable Frequency Drives as that is another way to run three phase from 110 or 220 and get variable speed in the bargain. Also, I believe there are comments about the torque loss from phase converters. (20497)
The simplest and cheapest way is to put a 1hp single phase motor in the beast. Its a frame 56 and wire it up for 220v operation. It is 1725 rpm nominal motor operation. I got a brand new 1hp Leeson motor on Ebay for $50 and put in in mine, works great. JP (20520)
I agree, I put a ? hp totally enclosed motor in mine and am running it on 115 volts and it works great. I had to rewire the barrel switch to reverse the starting winding connections but that is not difficult and it is covered in the files. Ray(20526)
When I got my 10L it still had the original 3/4 hp., 3 phase motor, so I bought a new dayton 3/4 hp., 66 frame motor. Bolted right in, all I changed was the switch wiring because I wired it 110. (20530)
Since I posted the question I came up with another question. When I called LeBlonde/South Bend to find out the date my lathe was shipped, the person I talked to told me if I change the motor I should get one with a "Soft Start". Is that a common feature on motors now available, and should it be labeled as such on the data tag? (20538)
Soft start, easy start, or slow start is usually a function of a motor controller. The controller starts a motor with gradual torque so it doesn't t snap the drive train. This also limits the starting current and supposedly increases the life of the motor. For single-phase motors, capacitor start motors have more starting torque than split phase or shaded pole motors but it is harder to find the later two in 1 hp. Ray (20552)
At a reasonable price you are limited to capacitor start. Starting torque is not an issue, you have a B size Vee belt off the motor and a leather belt off the counter drive. Most machining on the lathe will be under 300 rpm spindle speed. You will appreciate the torque generated by a 1hp single phase. The original was a 3/4hp 3 phase motor. Motors were rated a bit different 50 years back. JP (20568)
South Bend 9A Motor Voltages
I am purchasing a SB-9A 'precision' lathe with under-drive and sheet metal cabinet. Kind of 'special' and both bit inconvenient to me is that the unit is 'American' or 'English' and not Metric as we are used to in Europe. The motor currently runs on 380V 3ph. but when looking at the motor tag it seems to 110,220 400 V. I think this unit may have been an 'army' version that had a multiple voltage motor to have it shipped wherever needed without worrying about power supply. Does anyone of you know whether these units ever have been supplied with this type of motors ?? and help me with a wiring diagram to have it re-wired for 230V single phase? Piet (21989)
Can you find out the actual nameplate details, especially the frequency (50 or 60Hz.), also advise what supply you have available? An Inverter will allow you to run a 3ph motor on 1ph. and will have side benefits, if you can afford it. Jim (21992)
You would probably be better off just purchasing a replacement motor. I can get used ones in the USA for US$20-40. It should be at most twice that in Europe. Gene (21994)
Piet, If you can get the manufacturer's name and the model number from the motor, you should be able to get any info you need. Mario (21996)
Piet, If the motor is 3 phase it cannot be run on single phase and generate enough torque to be useable. You need to change the motor to a single phase motor or feed the motor you have with 3 phase power. JP (22001)
JP, With a phase converter, I believe you can run a 3phase motor on single phase service not at full power, granted, but reasonably effectively. Mario (22027)
A phase converter actually creates three phases. A static converter takes the input power, converts it to DC and then makes a 3 60 Hz signals or 3 phase. These cost as much as a new single phase motor. A dynamic converter uses a larger 3 phase motor to create the third phase. There are cheating converters which are just starter caps in series with one of the windings of the motor. The motor will run but it won't have much mechanical power. These are cheap but useless. JP (22030)
Piet I don't think your motor will re-wire to single phase, occasionally one of this type will but they are very rare and usually so marked as extra capacitors are needed. Best option, as it is a 3 phase, is to get an electronic variable speed inverter. Much nicer to use and, for a smaller motor, not vastly more expensive than a good quality single phase replacement. If you want to convert to metric I suggest you source good used Boxford feed screw and dial parts from the UK and make the minor modifications needed to fit them. A Boxford 100/127 metric conversion gear will also be needed. Ought to be possible for around € 200 or less. A metric converted English S-B is actually easier to use for screw-cutting than many nominally fully metric lathes! (22033)
Gee, I wish I had know that before I built a rotary converter from a three phase motor, and capacitors that came off scrapped air conditioners and compressors at a local recycling center. Even worse, I've been using it to power my Yates-American wood lathe that has a 1/2 h.p. 3 phase motor. I've been using it for about 5 years, doing some VERY aggressive turning, and never even noticed that it didn't have any power!?!? I apologize for the sarcasm JP, but when people making blanket, absolute statements, even though they are based on fact, they can be very misleading, unless you know all assumptions that the statement is based on. I know that a three phase converter doesn't really develop "true 3 Phase" power. (At least that's what I've read... I am by no means an expert in electrical equipment) I have also read that when run on this type of power supply, a three phase motor does not develop full power. (if you listen to the "experts", the estimates I've seen vary from 50 to 75%). But it is also true that this can be a very cost effective way for a home shop machinist to obtain and use a quality machine tool that he or she might otherwise not be able to afford. I suspect there is more than one person on this group who is operating a 3 phase machine tool this way, and are quite satisfied with it's operation. With regard to the reduced power, remember that many of these machines were designed for industrial use, with a safety factor. Even at 50% of the original power most home shop applications will never exceed the available power. Again, I apologize for the sarcasm, but please let's all be cautious of making absolute statements. As Abe Lincoln once said, "Be careful of the words you speak, for, tomorrow they may be the ones you eat"! Mario (22053)
No problem Mario. The rotary converter is another animal all together. The cap start and cap run 3 phase motor becomes the generator of the third phase and is probably the best way to generate it. I use it here. The trick is to have a larger motor as the generator than the one used to power the tool. Ideally there should be a start cap and run cap and centrifical switch and the system should be balanced for optimum efficiency. The rotary converter needs to be started and come up to speed first. I didn't want to get into a long explanation before. My intent was to warn not to bother with the 'el cheapo' power converters which seem to be peddled by many of the Asian tool peddlers. I do not want the get into a 'how to build it' rathole, been there, done that. I know NOT-TING! Schultz The static converter that I previously mentioned and the rotary converter do produce true 3 phase power. Each one can cost a couple of hundred bucks list. It can be cheaper to buy a single phase motor. The capacitor ONLY does not produce 'true 3 phase power'! If it looks like a motor or has a circuit board and some big transistors inside you are probably OK, if it just a capacitor or two (looks like a small can) don't bother wasting your time and money. JP (22056)
Just to back-up what Clive said previously with reference to the motor, To convert it to single phase you need to find out if it is wired in the windings to 'star' or 'delta'. On a modern 3 phase motor this is easy, by looking in the terminal box there are 6 terminal posts with 3 link plates. For 230 volt operation, the coils are connected in parallel (or across in pairs), for 460 volt operation they would be linked in series (all the posts on one side connected together. In an older motor the 'star' joint is internal so you need to go into the motor windings and find the 'star' joint, separate them and extend each to the 3 posts in the terminal box. Once the terminals are set correctly you need an in-line capacitor to make the whole thing work. If you are taking this route find an electrician, it is dangerous to get it wrong. The second suggestion is a better although more expensive route. A frequency inverter gives you ultimate control of the motor with very little loss of torque, a single phase supply running a 3 phase motor. With the use of a remote, this allows controllable speed up and down the range at each belt or gear position and also excellent reversing. I will be going this route when I get an inverter I have the motor waiting. I know a few people who have been machine operators for a number of years and that use the inverter method and they sing its praises as a god-send to any machine control use, they have them fitted to lathes, mills, shapers and drills. Terry (22061)
I converted a Record wood lathe about two years ago it was a Brooks 1ph. flange mounted motor with a long shaft and four step multi vee belt pulley. VS was the aim, changing the motor would have been expensive Staying with 1ph would have limited the bottom speed and complicated starting. So the motor was rewound to 230V. 3ph. and operates to 1800rpm @ 60.5Hz. and to 2625 rpm at 90 Hz. Changing the belts optimizes the performance at the lower speeds, otherwise it is usually left at its last setting. Control is by an old Dictaphone foot switch modified to provide start/stop. Forward/ reverse and speed controlled at a wall mounted panel. Speed is preset by a pot or three binary coded toggle switches. Acceleration is ramped to minimize inrush, dynamic braking is available but was not incorporated - yet. I used a T.B. Woods inverter operating from 240V, 1ph.60 Hz (22067)
Model 9A motor replacement
I need to replace the motor on a model 9A and have no idea what the specs are. This is reversible and runs on 110V. Can someone tell me what HP and rpm I should be looking for ? And where a good place to buy one might be? Ed (22360)
If an older (several decades old) motor anything in the 1/2 to 1 HP range should work fine. If a more recent model something around a 1 HP is needed. On the older motors 1HP = 1HP. On today's motors 1HP = something the marketing department made up. As to a source - contact me off of the list g Dayton motors a couple of which appear never to have been used. Otherwise Ebay is a cheap source. If you want to buy new I recommend Graingers. They're the most expensive but the service and support is fantastic. You might want to consider adding a variable speed control. This used to mean switching to DC but supposedly the cheap AC control units work well for motors up to 1 NewHP. I should be finishing up my AC system this week and I can let you know how well it works. Assuming the controller works well the main downside is that you have less torque compared to using the reduction pulleys. Gene (22361)
Ed, the factory motor is 1/2 HP and 1725 RPM continuous duty, 3/4" shaft. RichD (22362)
How are you doing this and what is inexpensive? I spent the weekend reading about VFD's and the consensus is that, while VFD's can be powered from single phase, they will not work on a single phase motor. There are some new units that will not but the least expensive one I found was $300. While its not a SB and a bit OT I would like to use one on my second Burke #4. Any suggestions would be helpful. Jim B. (22365)
I bought a GE 1725 1/2hp reversible motor at our local farm store about $140.00. I also bought a version of the same motor for another machine from www.grizzly.com for 1/2 as much but its made in China. The GE is from Mexico. Bob (22367)
You are correct they are expensive. They are commonly used on 3 phase motors because that is where the biggest market for them is. If it is going to double as a static converter then it might be worth the cost. Consider a DC motor. I have picked up new ones on Ebay for $50 and the drive for $20. The other thing to consider is, do you really need one or is it just posh to have a VFD? I only use 3 speeds out of the 9 available to me. JP (22369)
It is being done by modifying a dimmer control. Under US$50 total. I've read positive results but want to see for myself. Graingers has one for $150. Gene (22372)
You can have a real VFD for $100 on ebay. Check item 3856062636. -- usual caveats. Some cheaper ones are available that use higher voltages or have less capacity. A VFD will work or can be made to work with a single phase motor but if you have it slowed down very much it's likely start vibrating due to the torque pulses. A three phase motor running at 20 cps is getting as many pulses as a single phase at 60 cps so vibration wont be as noticeable. I'm not so sure of the one Gene has found. From the description it doesn't sound like a true VFD. Personally I'm still in the low tech world of swapping pulleys. John (22377)
Check out www.surpluscenter.com Good source of motors and lots of other stuff. (22379)
We have a similar source in Canada. http://www.princessauto.com Dean (22380)
I found an agricultural 1 hp motor in Harbor Freight for my 10" heavy and it works fine on 110volt with the original reversing switch that is on the Lathe. Gene (22382)
The motor on my 1946 model A is a Dunlap 1/3 hp, split phase ball bearing motor sold by Sears, Roebuck. The spec plate indicates 1750 rpm 5.4 amp. The number at the bottom of the plate is J1 46 which I believe is a date code. I am second owner of this particular lathe, and I have every reason to believe the motor is the original motor, and it runs like it's new. As for power, belts slip before the motor bogs down. James (22383)
The link only points to a fan or universal motor control. A true VFD will start at around $200. While they accept single phase input, a true VFD can only control a 3-phase motor, as the windings can better respond to varying of the Hertz. A single phase induction motor, designed for 60 hz really hates being run on 50 Hz electricity as it throws off the timing of the pole switches needed to sustain motion. I have a European mill, and it shipped with a permanent split motor, because PS motors don't mind a changing of the input Hertz as induction motors. The mill now has as VFD and three-phase motor. There is no torque loss when using a VFD if you stay within a given HZ range. For example, my VFD drive has full motor torque between 20 and 60 Hz. Torque rapidly decreases above 70 HZ. The expensive "vector flux" type have full torque from 0 to 60 HZ, as torque is a factor of RPM. Gabe (22405)
The Grainger is used for PSC motors. not what one would use for any torque on starting. I tap on the lathe enough that I need the power. Dave (22650)
But as was noted, 1/2 hp is not what it used to be. My 9" A had a 1/4 motor on it. Sleeve bushing on the pulley end that is worn with nearly 1/8 inch play. I would like 1/2 to 3/4 for the replacement. Has there been any discussion of 110 vs 220 ? as regards power ? Dave (22651)
I just check out Griz and they offer both open and TEFC. both my lathes are open, but I always felt a TEFC would be much better. Wadda youse guys use ? Dave (22652)
Another option is a motor rewinding shop. Check your phone book. I picked up a nice 1/2hp for $25. JP (22653)
I have a 10" Heavy with a single phase, 220 VAC instantaneously reversible motor. (yes, single phase) Go with 220 as it uses less AMPs and thus your electric meter goes slower. (although on a small lathe that may not be a really big issue, esp. in a home hobby shop versus a production plant). Eric (22654)
Dave, Yes, I should have added Cap start. Mine is original 1946, even had the SBL marked V belt at one time. This is all the power one needs on a 9" lathe. 120 vs 220 on a 1/2 HP motor is really just what ever is convenient to you and the wiring condition and configuration at your site. It makes no diff to the lathe operation. The start winding is 120 only anyways. RichD(22655)
Eric, SORRY, BUT THE WATT HOUR METER WILL SPIN AT THE SAME RATE. Power is power. 110 V at 7A is identical to 220 V at 3.5A. HP and watt hours don't change. BTW, you are required to use the same size wire in the home, so there is no change there either. RichD (22656)
I think that the 220 balances the load automatically so it is possible there will be some slight savings just from the efficient use of the power. Not that any more or less is being used. Second, residential wiring it typically 12ga for receptacles for 20 amps, to in that area, there is no benefit. Adding a dual circuit breaker would offer a slight additional cost, but not much. I was thinking more on the lines of more torque or something with the 220. Dave (22657)
I use TEFC whenever I can. MUCH easier to clean any oil off and no danger of chips or oil in the windings or centrifugal switch. I think this is more of an issue for the horizontal drive machines than any other. Ed (22658)
Nope, no savings. The biggest expense is in panel space. (22660)
Dave Quite often fractional HP motors were TENV in 70's and later. HTRL shows the 9A as only needing !/4 HP?. The life and frame size of a motor depends on the type of insulation it is wound with, look for type "B" insulation as a minimum. If the motor was mfd.in compliance with NEMA stds. then it is designed to run at maximum load, in max. ambient for 7yrs. before the insulation deteriorates to the point where it will no longer withstand the normal transient voltage surges This is not valid for frequent starts, but 9A lathe service would not be a problem as far as starts are concerned and sustained runs at full load are impossible in the application. So 9A lathe service is well within the designed capacity of a NEMA design motor. It is more likely that the motor will fail due to lubrication problems if it has sleeve brgs which are common for fractionals. Many orig. motors are open drip proof and even assembled with the air ducts upwards begging for swarf to enter and cause shorts in the windings. Most rewind shops will use a better insulation than original, therefore if the choice is yours get an enclosed motor and if you have physical room I would recommend the largest you can fit in the space and handle electrically, prob. 1/2 - 3/4 HP. The larger motor will better handle interrupted cuts, carbide tools etc. without significant loss of rpm. It is possible that the generous motor design of the 1/4 HP, the available space and the motor cost had a bearing on the original SB 1935 motor selection. Hope this is of some interest and help to you. Jim (22665)
I tend to lean towards "open drip proof" motors. I have used then for over 20 years on my lathe and never had a problem. A TEFC will work just fine but usually they are more expensive. A TEFC motor has much heavier windings than a open drip proof motor of the same horse power because of the poor heat dissipation of the motor. The internal fan has to transfer heat to the case and the external fan has to circulate air over the case to remove that transferred heat. This is much less efficient that circulating outside air through the motor. These heavier windings add to the expense of the motor. I have read somewhere that a 1/2 HP TEFC motor is built to the same internal wiring configuration as a 1.5 to 2 HP open drip proof motor. Of course, TEFC motors are safer in hazardous environments where explosive solvents, gases or combustible dust is present. If you are running a coolant system on a horizontal drive lathe, then TEFC would be the way to go. Otherwise, I would stay with an open drip proof motor. Webb (22666)
The windings in a TEFC motor are generally identical to an ODP motor the difference is that an ODP motor would be capable of a 15% thermal service factor and the TEFC zero service factor, no more torque, no difference in electrical power. Which means that in a small lathe application, in the usual ambient temperature and ignoring neglect, lightning etc. the ODP might last 60 yrs. and the TEFC motor only 40 yrs. If you were as old as I was before I got a lathe: who cares? With either motor you might expect about 150% torque short time overload capacity with about a 10% loss in RPM Providing your wiring and power system will support it. Your ODP motor will be capable of longer short time overload, but in a lathe with the recommended motor I doubt if you would ever know the difference. These statements are not valid for Oriental motors, my opinion in that regard would favor a used NA motor especially if it has new bearings and upgraded insulation. After an hours running, If can barely keep your hand on the outside of the motor it is not being overloaded. If it growls, your too late. Jim (22677)
I looked at the 1/4 hp motor I have that came with the lathe. Unfortunately, it is a sleeve and not roller bearing type, which is why it is having problems the sleeve is worn. I am thinking about re-sleeveing it, but I have not found any data on the web regarding how to do that and if it is advisable. I have an old HF drill press motor, looks tiny in comparison, but would serve if I just wanted to spin the old motor armature to grind the shaft or to make a new sleeve. I'm not sure if there is enough room in the cast housing to install a roller bearing. Maybe one day when I do castings, I'll make a whole new end.... I do have a treadmill that looks interesting, have not pulled the electronics out of it to see how it might be used. It says it is a 2 hp motor, has a variable speed drive and is listed as 90 volts DC. I have no idea of the starting torque of such a motor.... odd that there is so little on the net about rebuilding motors. Dave (22682)
Dave Talk to your local rewind shop about new bushings and grinding the shaft they will probably do it more efficiently. Or better still sell you a recond. motor with some type of warranty. Or take your chances on EBay. If you have a controller already, the DC motor. would be the good choice, subject to some reservations- Is the field permanent magnet? - Is it separately excited shunt. - Is it Compound wound? - do you have the controller to match the motor. At 90Vdc the motor will draw 19 - 20 Amps when developing 2 HP but at roughly 1/4 HP demand load it will only draw approx 3.5 A or a little less than a 1/4 HP single phase motor at full load, it all depends on the starter. Local codes and insurance coverage will require wiring to support the motor nameplate Amps. If you answer the questions posed above I would be better able to help. Whose make is the motor,? the controller? Are they NA. What is the DC motor frame size? what is the AC motor frame size? The 90 V usually means it is a PM shunt motor and the package was arranged to be plugged into 120Vac outlet supplied from a devoted breaker. If the Treadmill is 10 yrs or so old, it likely would meet all your needs except reversing, and this could be easily done in a separate toggle switch or similar device in the armature leads and interlocked with and arranged to be operated before the motor can be energized. Jim (22689)
I read the label wrong, it is 3/4 hp, 8 amps. I have not salvaged the control panel and motor from the machine. I want to do it carefully so as to not ruing anything that will be needed. There are a lot of selection switches on the operators panel with multiple settings. I'm hoping I can get it so that I have a pot and a power cord. As I get deeper into the disassembly, I'll ask more questions. Dave (22690)
Dave That's more like it. With 2HP I did wonder if it was a Elephant Treadmill. Where are you located? I'm in Toronto. Was the TM in a hospital, a Cardiologist's office or just a Gym? The one in my Cardiologist's office is quite sophisticated. I'm sure the drive is separate from the instrumentation. I have a friend who services TMs. I may be able to tap that resource. Jim (22691)
Where are you located? I'm in Toronto. The one in my Cardiologist's office is quite sophisticated. I'm sure the drive is separate from the instrumentation. I have a friend who services TMs. I may be able to tap that resource. I was lucky enough to get this one curbside. The belt looks brand new and there is no telltale dust under that would indicate much use. Not removing any of the covers, the lower end looks like there is a small circuit board with a few pots and a relatively small transformer. I'll be taking lots and lots of pictures before I open it up. I find that having about 17 different angles on each thing, it is easier to re-assemble. If there is much complication, I may be in over my head. if it is separate boards then the pot may just be a remote connection to the power controller. Heck, even if I can get a single speed out of the thing it would be neat. I am interested to know the torque curves of such a motor. Since it is rated at 3,300 RPM I would like to get it to run at a lower speed. In peeking thru the holes, I did find one that may have been the killer. There is a hole that looks kinda torn up and inside of that the circuit board is damaged. More to follow. Dave (22694)
Dave The TM motor you have is most likely shunt characteristic, but with a relatively sophisticated controller (before the holes appeared). The treadmill application would require controlled acceleration therefore the motor would not require the typical drives have some type of controlled acceleration to protect both the motor and the equipment. NC lathe axis drives have very high accel. rates but are designed for that duty. Trying to start across the line is not advisable. If your TM motor is shunt at 90Vdc for 3300 rpm then it will only require 49 Vdc to run at 1800 rpm. The problem is that your !/2 HP will then only be rated at 0.27 HP. Your simplest solution might be a step down transformer to 50Vac, a powerstat and a full wave rectifier bridge, always starting at low voltage and manually turning it up to the desired rpm to avoid commutator damage. Jim (22710)
Leemme see if I understand. Create a simple unregulated power supply for around 50V DC. Power it from a amp rated variac and start at a slow speed ? Then using a DPDT relay, again of rated voltage, connect the motor wires for a FWD/REV switch. If it is that simple, I'm THERE ! Dave (22711)
I haven't been following this discussion much, but there is a place where you can usually find either new or take-out treadmill motors. They usually have some of the specs there too. It may be of help. http://www.sciplus.com/ C (22712)
Bingo! Since the motor is actually rated 1/2HP at 90 Vdc. FLC would be about 5Amps. Full load torque will still demand 5 Amps at 50Vdc for 0.27HP at 1800rpm. So size elements and wire to support 5A. Jim Waugh (22714)
My background was heavy industry. I have only a "clinical" interest in treadmills. Your comment is appreciated never the less. Jim (22715)
Full load torque will still demand 5 Amps at 50Vdc for 0.27HP at 1800rpm. So size elements and wire to support 5A. Darn, and I just tossed about a 150 pound power supply, huge transformer and huge inductor with huge caps... I think it was a 50 amp power supply, would have been perfect. I have a 20 amp power supply capable of being wired for anything from 7 volts up to about 70 volts, but the cap is limited to 70 volts so the 40 volts would be easy enough to do. I stated pulling apart the electronics. half of the unit is a serial connection for different programs. running up and down hills for different times and such. The display is in MPH, but I may be able to use that for RPM of some reference. If I can use the electronics, I'll go that route, but will put together a simple power supply anyway. I'd like to put one of these on a drill press. I really want a reverse for when I tap on the drill press. Dave (22716)
Interesting, they have a 1.5 hp so, if the speed is reduced, then the power will be reduced also, that means it would be more powerful than the one I am looking into. I may also look into a jackshaft arrangement to get the full motor speed and a lower lathe speed. that would be more hp to the lathe. Interesting thread. Dave (22717)
Dave One more goodie, I find an Ammeter handy on a lathe. Mine is an old ac moving coil instrument connected in the line between the Variac and the rect. bridge but it is scaled 0 - 150A It is a 5A movement and would otherwise be used with a 150 - 5A current transformer. My motor is a 1/2 HP. 5A. 90V so 5A is full scale. Reasonable overload is OK say Jim (22719)
It looks like that my earlier statements were in error. I talked to a engineer over at Reliance - Rockwell Automation and he informed me that in large HP motors, there is a difference in the gauge, core length, rotor size, etc. and that if the end bells of a TEFC motor were replaced with ODP type end bells, the motor would be capable of higher HP output. BUT in small fractional HP motors, the difference is "Practically nothing at all..." But there can be a difference in price. I was looking at Dayton motors and the prices for 2 HP TEFC were about 20% higher than ODP of the same HP, construction and frame size but some of the smaller 1/2 HP motors didn't have any significant difference in price at all. The only time I ever had problems with an ODP motor was many years ago on my father's table saw. There, sawdust would get into the contacts for the start windings and I would have to blow them out with compressed air and the saw was good for another two (or more) years (ah, the days of youth). Anyway, my apologies to the group. Webb (22726)
My motor is a 1/2 HP. 5A. 90V so 5A is full scale. Reasonable overload is OK say continuously. For the ammeter, it uses a shunt ? no ? For AC one would use a current transformer, but DC needs an actual measurement. I have a few different gauges, some are really neat, some the old round style, some are the newer square style. But, it sounds like a neat addition. With the variable speed I think a RPM meter is called for as well. I'll put that on the wish list too ! Dave (22731)
Dave In the circuit discussed the rms current from the variac is directed through the armature (inductive load) via the rectifier as unidirectional pulses (not true DC) but don't tell the motor and it will never know. Jim (22734)
ummm.... transformer (Variac ?) to a bridge rectifier = choppy DC waveform. Add a filter capacitor or a inductor to get a filtered DC with close to peak voltage (not RMS) with a cap, it is 1.414 times RMS AC (less the bridge voltage drop) for the inductor it is almost RMS voltage level. If I put on a variac as the transformer, or use one before a transformer and then use a fill wave bridge rectifier, I get a choppy DC voltage, if I add a cap, I get a smooth(er) DC voltage. I'm confused as to which style Power Supply would be best. I already have 10 a 10 amp variac and a 10 amp 110:48 xfrmer and a 80,000uF 100V cap so I have all the parts to do it any way but with a inductor (choke) as the filter. Dave (22736)
I just pulled all the guts out of the treadmill and found a DART controller. This is just the ticket. It takes all the fancy gizmos out of the picture and they are all replaced with a simple 5k pot ! With this simple set-up I lose the speed regulation feedback from the hall-effect sensor, but that went thru three separate PC boards. Unfortunately, the model that DART lists does not cross reference to the label on the unit. Seems the DART-150 controller is not listed on their site, which leads me to believe it is an OEM unit. I hope it wires up like the 125 controller as it appears to be very similar in many ways. Anyone have any idea about this thing ? Dave (22744)
After a little playing with the unit, I put on a pot and get simple speed control, but there is a fixed ramp speed. I'm not sure just how much power it will have while ramping. Since I tap on the lathe, I need that low end torque. I'll have it on this weekend so it will be nice to spin the lathe again after the 6 month hiatus. Since I have not found out if will be any low end torugue, the jury is still out if this is an upgrade, or if it is just another wasted effort. Dave (22762)
Dave, all the Dart, KB and Minaric drives I've seen and used use back EMF feedback from the motor to control speed and maintain torque. These are great and almost bullet proof drives. Surplus Center sells Dart drives. Does your have the 4 mini pots on the board for min speed, max speed, torque and comp? RichD (22763)
It looks just like the 125 board. yes, it does have the 4 pots. In a very crude, slow speed test, it was pretty easy to slow the machine down with my hand on the flat belt. Not promising for slow speed use. Dave (22765)
Dave, you should try adjusting the comp and torque pots. That's what they are for! A similar controller by KB Electronics is used in all Sherline mills and lathes with a DC permag motor. Full torque at all speeds. I am running a Sherline 5400 mill CNC today engraving and milling. RichD (22767)
New Motor?
I'm not really sure what I should do... Purchas a hole new motor (110v 1HP or greater) or build a rolling phase converter. I know you don't get full power out of a static phase converter, and there may be other drawbacks to using a static phase converter, But I wonder if the same power concerns hold true with a rolling phase converter? But anyway...aside from the power loss or gain. What is the pros and cons of the three configurations? Yeah 110v would be convenient, but somewhere in the distant future I am likely to get something else that is three phase. I guess I could always upgrade the three phase motor to a faster model and use a VFD? I guess that adds a fourth option. Really. What do you folks recommend and what has your experiences been? (22985)
With a rotary phase converter, it will run at full power. I made my own Rotary Phase Converter and it cost me about $150 with a 5 HP Three phase idler motor. Jim (22987)
If you visit junk yards, you should find a junked 3 phase motor without much problem and in decent condition. Since a rotary phase converter is easy to make, that would be my choice for a larger lathe. If you buy new, then you need two 3 phase motors. Also, from what little I have read, get a larger idler motor, like a 50% larger one than the drive motor. The single phase option is easier of course. Grizzly and Harbor Freight sell sell motors for under $100.00. Dave (22994)
 If you have a true static phase converter then you will get full power from your motor. They cost a couple of hundred dollars. A new single phase motor is a little cheaper. I picked up a 1hp Leesom single phase motor on ebay for $50. A rotary phase converter is a larger 3 phase motor plus starting capacitors and run capacitors etc. They work well. The rotary phase converter has to be up to speed before you start your lathe. You will get the same power from your lathe motor with it that you get from a static phase converter. There are capacitor boxes which go cheap and are sold as static phase converters and they are really not. These don't allow you to get much power from your motor. A true static phase converter has a printed circuit board and some large transistors in it. A VFD is a static phase converter that allows you to vary the frequency to vary the speed. This is the most expensive solution. JP (22995)
Go with the single phase, it's the most flexible since it's available everywhere. New and used motors are plentiful and reasonably priced. It will also increase the value of your lathe should you ever decide to part with it, given that those interested in it would likely be ones with home shops. A phase converter will likely cost more than a motor and use additional power, although that usually isn't a real consideration in a home shop. However a rotary converter will also make noise as it consumes power! As in most cases, less is more. Roy (22996)
VSD can be had from E-Bay for less than $200.00 so if you already have a motor, this may be a cost effective solution. Dave
(22997)
A rotary phase converter is a larger 3 phase Dave/JP , if you use the VFD to reduce motor speed , what happens to the motor o/p torque ? One of the HUGE benefits of the c/shaft system (or [back]gearing , equally ) must be that as speed at point of use is dropped , the applied torque is automatically INCREASED (ie exactly what you want ! ) . My cheapo electric hand-drill has trigger-sensitive speed control , which is great for starting , BUT when the speed is reduced the torque goes out the window . Does it reduce speed by chopping the waveform , and therefore the available power also ? Also, are there any guides out there for rotary converters? I know zilch about them . Are they S/P motors mechanically strapped to 3/P alternators, or is that being daft ? Tim (23000)
Not necessarily so A new 1 HP 230 single phase to 3 Phase VFD can be had for about $160 I built my RPC using a 1 « HP e-bay motor I got for $25. then the shipping added about $20. I got 12 dual caps for $17 the shipping added $6. I needed a box. A 10 by 10 by 12 electrical box went for about $20 at the electrical store. I use a push button to start it, (cheaper than a relay) $6 at HD Needed wire and crimp lugs. By the time I was finished it cost just under $150. Not much of a difference and you get speed control with the VFD. I am going that way on my second Burke. BTW a usable 1 HP VFD went on e-bay for $50 Jim B(23003)
The capacitor type phase converters only start these 3 phase motor. It still runs on single phase but only 23 power. The rotary type uses another 3 phase motor of equal or greater hp to generate the third phase. It also uses capacitors to start the 3 phase generator motor and after its` running the 3 leg is connected to your lathe motor. I would use a single phase motor just for simplicity. It's not all that expensive. (23004)
Tim, The motor speed is proportional to the frequency of the drive signal, the VFD generates the drive signal and the frequency is adjustable. The torque is directly related to the motor efficiency at the operating frequency, usually less than full speed but not as bad as the light dimmer type you mention which chops power. There is no motor/generator like the old WW2 dynamotor. The rotary phase converter is a larger (150% to 200%) 3 phase motor which runs off of capacitors. It in itself does not run with full torque but it does, by its own mechanical motion generate the third phase so a smaller motor can run from it at full power. The converter and its load are wired in parallel. This is why the converter has to be up to speed first to work. It is nothing more than a 3 phase motor, a start capacitor bank and a run capacitor bank and a switchover relay. The switchover can be manual. A RPC can operate more than one motor providing that the total load is less than the RPC rating. JP (23005)
This has been very helpful. I am just going to purchase a 110v motor. But now the question is how to wire it in? (23006)
You also asked how to wire. What do you have? Magnetic starter or drum switch? Momentary push button control? My Heavy 10 had the original Furnas mag starter and momentary switch bank still installed. By using the original Southbend wiring diagram available here and the motor wiring diagram available from the manufacturer (Marathon motors), I was able to rewire the starter single phase. The only portions of a mag starter that are voltage sensitive are the magnetic coils themselves and the "heater" fuses. The mag coils are, by definition, single phase and can usually be wired for 220 or 110. 440 machines usually have the magnets wired 110 and use a voltage reducing transformer. The heaters can be bypassed if you buy a motor with internal thermal protection. Otherwise you would need to size the heaters appropriately for your new motor. You need double 3 circuit mag starters to reverse a 110v motor and double 4 circuit starters for 220. An add-on microswitch safety interlock may or may not be needed to prevent simultaneous starter activation. If both starters close, you short out the circuit. For 1hp or less, a drum switch is easier. Also, 1hp is the absolute max you can run off a 110v 15 amp circuit. If it would help, I could post the wiring diagram I used here or at my website. Regards, Bill PS- got the new capacitor (4 bucks at an electronics surplus store) installed and my Heavy 10 is running now- I am a very happy camper. (23007)
Wiring info in the files section. JP (23008)
I have read with interest the many submissions on the subject and have the following comment. For the homemades, where did the labor costs go? At the very least it would have an impact on the time available to read your E-mails. What about terminals, hardware wire? What about feeder cable, breaker and starter for the 5Hp? What about circuit protection for the 3ph. output.? What about gas and car expense traveling to junk yards? What about workshop real estate value? What about fire insurance risk? What about increased power cost? What about non-operating power cost when lathe is not running? It seems to me the VFD has a considerable edge even before considering its many technical advantages. You can use 1ph. input. The Ampere rating of the power transistors has a bearing on the unit cost. The 3ph. rating of a unit will be larger than its 1ph. rating. 120V. 1ph. will draw more current than 240V. 1ph. and may put you into a unit with larger power transistors. But you should use a 240V. 3ph. motor or get your 120V.1ph. motor rewound to 240V. 3ph. - Much better than a new oriental motor to vacuum cleaner ratings stds. You will get rated torque to 60Hz. motor speed You can get rated HP. to 90 Hz. motor speed. You will get low voltage control for - start, stop, reversing, variable speed control. Programmable ramp up to set speed (minimizes voltage drop during starting). Limited ramp down unless you add dynamic braking option. Digital read out of performance and faults. In my opinion the VFD has it hands down! but make sure it has C/UL approval. Jim Waugh (23011)
The files section needs a little housekeeping. Also, when you buy the drum switch, it will (should) offer a wiring diagram. I think the wiring has to do with how the switch needs to be wired. Relays can be used, but are typically not a good idea unless you have an interlinked two speed or reversible contactor. There is always the possibility of one relay being stuck closed and the other creating a dead short. Dave (23017)
Are we talking logic or some deep rooted need to be among the bits and pieces of mechanical inspirations that others call 'junk' ? Long ago I learned that problems go away when you throw money at them. But part of the fun of a home shop is making the pieces we use. There is no doubt that I devalued my 9" by using a treadmill motor and DC drive. I will probably e-bay it in a month when I catch up on the back-log and then buy a new Grizzly or some such. If you have a clean and neat shop, the VFD is the clean and neat way to go. First class, with plugs or a contactor, you can run different machines as well. The rotary is the second best way as it offers the most power, but also costs more to run. But, I think the watts are somewhat proportional to load ? idling, it uses much less than when loaded ? As for the cost of visiting a junk yard, to me, it would be .. cost of trip, $9.00 cost of scrap $25.00 rummage among history ? priceless ! Besides, there are often neat things to be found. I got a 6 ft length of 1/2 ACME for $1.00. Dave (23018)
Motors/controllers: too many choices
Having spent the last year scrounging (rather successfully) and jumping on a few eBay specials, I am now faced with an embarrassment of riches in the area of variable speed motors and controllers. But I'm not completely clear in my own mind how best to deploy them to my lathe, my mill, and my drill press, and so would ask here for any thoughts or advice. 1. I have a 9" SB located in basically a hallway. There is SO little room that I cannot use the stock large intermediate pulley (that's driven by the motor and drives the flat belt pulley shaft). Instead, I have a 6" diameter pulley, which is ALL I have room for. With the tensioner applied, the pulley clears the wall by about 1/4". With the tensioner released, the motor strikes the foot of the bed, with the pulley now being about 1" away from the wall. The motor in question is a 3/4 HP DC motor, with variable speed controller. My strategy has been to set the flat belt for the lowest speed option. In combination with the smaller intermediate pulley, this results in an RPM roughly comparable to the highest speed of a stock SB. That is, my lowest speed matches a stock SB's highest speed. When lower speeds are called for, I simply reduce the speed of the motor. This strategy has worked quite well, EXCEPT for the fact that the motor is a PM DC motor, and so attracts chips like crazy. I've built a shield around it, but even so, some swarf gets through. I'm worried that one day, the swarf will get somewhere electrical it shouldn't, with bad consequences. 2. I have a Burke HMill located in an alcove about 36" wide and 36" deep. Getting to the back of it is almost impossible, and even getting to either side is _really_ tough. (Too much crap stored on either side. Long ago, I ran across a 2.5 (fake) HP treadmill motor, running at 4300 RPM at 130 volts. I slow it down to roughly 1500 RPM through a belt and pulley arrangement, then slow it down some more, to about 300 RPM, via another such setup. Final speedup or reduction is via the stock pair of Burke pulleys. Of course, even with all of this reduction, the spindle is still turning too fast for large cutters, so then I'm back to the KBElectronics DC motor controller to slow it down some more. This too works OK, but I just don't like all those belts and pulleys and I especially don't like the motor, not for a moment believing the power rating. 3. I have a generic Chinese 15 speed drill press with a "1/2 HP" motor about the size of a decent razor. Works fine and is actually accessible, but again, always either changing belts or (more usually) running things at entirely the wrong speed. So, here's the motor/controller combinations to choose from. 1. 3/4 HP DC motor and controller 2. another 3/4 HP DC motor and (homemade) controller 3. "2.5" HP DC motor and controller and insane reduction system 4. 1/2 HP VFD and either a simple 1/2 HP 3phase motor or another 1/2 HP 3P motor with kinda integral 7.5:1 worm reduction unit 5. 2 HP 3phase motor with matching VFD controller I'm leaning towards a. leaving the SB alone with the otherwise working 3/4HP DC motor b1. using the second 3/4HP DC motor on the Burke, but with only two belt reductions (as opposed to the current 6 pulley/3 belt system), or b2. using the same motor as above, but with some sort gearbox to do the initial speed reduction. Sadly, the (PacSci) motor is not a C mount, and so any of the standard gear reduction units are not easily utilized, or b3. using the 1/2HP 3P motor with gear unit. I almost like this idea, except that my experience with 3P motors (with VFD) and DC motors (with nice controllers) is that DC motors seem to have _way_ more power at lower speeds. c. using the 2HP 3P motor on the drill press. Total overkill, but it would allow a WIDE range of speeds while still providing lots of power for largish drills at low speeds. d. maybe using the 1/2HP 3P motor on my 6" AAMCO shaper or maybe my 4x6 bandsaw. As I said earlier, an embarrassment of riches; any thoughts appreciated. Alan (25105)
As far as DC motors are concerned you need to understand the Torque/Speed relationship. Motors develop their maximum power at half their rated speed, at zero and max RPM they produce no torque, following a bell curve. For a better understanding look at the write up at this site: http://lancet.mit.edu/motors/motors3.html#powercurve If you have set your pulleys so maximum motor speed occurs at the lathe's maximum RPM, depending on which model 9 you have that will give you 680 max. The lowest gearing, depending on the model you have, will be 50 RPM, this is a ratio of about 14:1 and your 3/4 HP motor will deliver less than 1/10th HP at that speed. True, the controller will try and compensate by increasing the voltage as the load comes on, this will increase the current flow, however at that speed there will be little to no fan cooling and the motor will run hot. I use a VFD on my BP look-alike mill, and it is fine if I take very light cuts at the lower speeds, but it is impossible to take a heavy cut without engaging the back gear and bringing the motor to somewhere near it's correct operating point. Bernard R (25107)
Bernie, That is input power consumed with a light load. The maximum mechanical power output from any motor is at the max rated speed. To properly match a motor to a machine you need to know the resistive and inertial loading of each item in the drive train and match them accordingly. As they become further removed from each other them you need to consider a controller to compensate for the difference. The torque is directly proportional to the current and the speed is proportional to the back EMF or voltage generated by the movement of the motor armature. This should be equal to the applied voltage. If you have too small of a motor for the load then you will get overheating. JP (25110)
I find the statements on the site you posted essentially correct but somewhat misleading, in that the implication is that the motor itself is the determinant of torque. DC motor torque is a product of magnetic field density and radial leverage on the armature. In actuality, the load is the determinant of applied torque IF THE SUPPLY VOLTAGE REMAINS CONSTANT. At zero rpm no back emf is produced so current is limited by the DC resistance of the windings and the internal resistance of the source. Torque is therefore at a maximum, BUT no energy is transferred to the load. With no load, rpm is limited by the balance between back emf and frictional resistance within the motor itself, and again, NO energy is transferred to a load. Applied torque is determined by the load, not by the motor. This is an important concept. By not recognizing this essential fact, the lesson that load must be matched to motor capability in order to obtain maximum efficiency is not clearly illustrated. This phenomena is analogous to the same in electrical circuitry, in which the load must match the internal resistance of the source in order to transfer maximum energy. In fact, it is an electrical transfer of energy, in which the electrical load resistance is determined by the physical load. When this is clearly understood, it becomes intuitively obvious why maximum energy transfer takes place in the midrange of the graph, because max energy transfer in an electrical circuit takes place when the source and load are matched in resistance. Jack F(25121)
Jack, The intent of my original response was to advise the original poster that there were inherent problems with depending solely on a motor controller to obtain useful power over wide machine RPM range. I agree that the site I listed takes the simplest view of the relationships and does not explain the family of curves obtained by varying the voltage. The site also does not go into heating effects, which is the crux of the problem, when dealing with high torque at low speeds. Your point on maximum energy transfer is well taken. Bernard R(25129)
I think I may not have asked the right questions first time around. I had no hope of getting "lots" of power (whatever lots means) over any kind of wide range. I was looking for something like about a 4:1 range with "adequate" power, adequate again being subjective; I'll derate appropriately when running slower than that. I do not think of my SB as a particularly rigid machine; about 1/3 HP seems like an adequate amount of power. Therefore, a 3/4 HP motor running at 1/4 speed _seems_ like I'm still in the ball park. I understand that electronics can't hope to replace an actual gearbox, given that when low speed is called for, high power is also usually called for (especially when milling). And a couple of quality computer fans can go a long way to keeping things cool. Perhaps I should rephrase the two questions in my mind. 1. Assuming industrial quality motors and controllers of similar capacity, at (for the sake of discussion) 1/4 rated RPM, what has more power; a DC motor with SCR controller (and back EMF compensation) or 3P motor with VFD ? 2. Someone told me once that he got a better surface finish when switching his single phase motor out with a 3 phase motor, the theory being reduced torque fluctuation per rotation. I wasn't sure I believed it, thinking belt stretch and inertia/flywheel effects would swamp out any such fluctuations. But I never forgot the comment, and am now wondering about it again. So here's the questions. Is a 3p motor likely to result in measurably or visibly better finish than a single phase ? And is a DC motor likely to be better or worse than a 3P? Alan (25132)
Alan, In the commercial world the tendency is to go with VFD rather than DC for variable speed, because it is newer or because it is better, there is no definite answer. Each application has specific parameters and all designs usually result in compromises. Better finish with 3 phase vs single phase? At full motor speed that statement would most likely be BS, VFD vs scr control with an AC motor at slow speeds you may see a difference because of the poles in an AC motor, not with a PM DC motor. You are correct on the belt flex/inertia compensation. Choppy motion shows up more in gear driven machines. Not meaning to repeat myself but to size a motor to a machine you have to match the motor inertia to the reflected load inertia. With a speed change figure in the square of the ratio to change the reflected inertia, yada, yada. Look up servo design, the same basics apply. Find the book 'Motion Control Design' by Jacob Tal, he shows a simple step by step approach. When in doubt, overkill with the motor. Hence a 3/4hp to 1hp motor on your lathe and more inertia for a smoother finish. Need a hard decision? Ok, if the costs are the same and you have to purchase new then go with the VFD and 1hp motor. JP (25135)
Alan, Given the choice I would always use an AC induction motor over a DC motor for two reasons, 1: a severe overload on a DC motor can permanently reduce the magnetic field, 2: no need to worry about brushes. Bearing in mind the torque limitations at slower speeds, VFDs and 3 phase motors are great, especially on a mill. The ability to run a spotting drill at 2000 then drop down to a few hundred for putting through a 1/2" drill, just with the turn of a knob is real handy. In practice I limit my VFD to twice input frequency, with the pulley ratio I have chosen this gives a speed range of zero to 3400 RPM, motor's rated to 5000, and back gear zero to 400. Three phase motors run significantly quieter and with less vibration than single phase and their torque curve starts as soon as the power is applied, as opposed to the single phase motor where reasonable torque is not produced until the motor reaches at least 30% of its synchronous speed. 3 phase motors are also smaller and simpler than their single phase equivalent as you don't need start or run capacitors or a start relay, they will also reverse instantly. the only reason we don't all run 3phase is the cost of installing the service. Bernard (25136)
Alan, I'm afraid I couldn't follow your logic- kind of an electric motor version of the shell game. However, this won't stop me from having an opinion ;-) Horsepower is a lousy way to chose a motor, in my opinion. What matters is torque at the machine spindle. Electric motors are essentially constant torque devices and horsepower is torque x speed / 550. Say you want to reproduce the rpm range of the three step pulleys using the middle pulley and a variable speed control. Your presently have a 1 horse motor and this is sufficient but you wouldn't want less torque. Moving the flat belt on a heavy 10 gives around five to one speed range. If you use the middle pulley, you need a motor that can operate between 700 and 3500 rpm and is rated at 5hp at 3500. One more thing, a VFD 3 phase motor will be synchronous so it will maintain the set speed. A PM DC motor is not synchronous and speed will vary with load. Although some of this can be addressed by sensing the back emf, encoder feedback is the only way to truly control a DC motor's speed. On the other hand, unless the 3 phase motor is designed for VFD control, it will get very warm at low speeds as the windings can oversaturate. Again, this can be controlled somewhat by clever VFD design but is tough to eliminate. The workaround it to limit the minimum speed.  Bill (25141)
Alan writes: So, here's the motor/controller combinations to choose from. --- b2. using the same motor as above, but with some sort gearbox to do the intial speed reduction. Sadly, the (PacSci) motor is not a C mount, and so any of the standard gear reduction units are not easily utilized, or b3. using the 1/2HP 3P motor with gear unit. I almost like this idea, except that my experience with 3P motors (with VFD) and DC motors (with nice controllers) is that DC motors seem to have _way_ more power at lower speeds. Discussing only this one issue, if you use a combination of belt and gear reductions 'tis best to put the belts in the higher speed part of the train. Belt drives don't work so well at low speeds and gear drives have fewer problems at low speeds as compared to higher RPM. JMHO Anthony (25145)
I see. Sorry, I just threw in my nosy two cents because the concept that max energy transfer occurs when source impedance and load resistance are matched is important in every field of energy transfer, and there is so much misunderstanding about this. Jack F (25155)
Jack, It is true that maximum power transfer occurs when load resistance and source resistance are matched. This doesn't' mean that your best choice of source resistance is the same as the load resistance. If source and load are equal, 1/2 power is dissipated in each. If source resistance is zero, all the power is dissipated in the load. Bigger is better. Glen Reeser(25162)
Glen, when you find a source with zero internal resistance you will have perpetual motion. G Maximum power transfer ALWAYS occurs when the source internal impedance and load resistance is equal. With less internal resistance means you can transfer more power with less load resistance. With zero internal resistance and zero load resistance you will have an eternally circulating current. Some of the the guys are working on that now with the supercooled conductors, but no zero resistance yet. Jack F (25164)
Jack, For a fixed source impedance, maximum power transfer occurs when the load impedance matches. For a fixed load impedance, maximum power transfer occurs when the source impedance is zero ( or as close as you can get). Increasing the source impedance will never improve power transfer. Ed (25173)
Now you are into nonsense. When did I ever say that increasing the source impedance improves power transfer? Your statement is also nonsense: That statement is a prime example of the popular confusion and misunderstanding of the very concept. What you are saying is that it is possible to draw high current with a very low source impedance. That is true. However, what you are disregarding is the corollary, that to increase the current the load resistance must be lowered. G Ultimately the load must match the source to transfer the most power. Simply increasing current with a low load resistance does increase power transfer, that is true, but only until the load resistance is matched to the source impedance. Lowering the load resistance below the source impedance will continue to increase current, but it will lower the voltage across the load, so the power transfer actually decreases. Calculus is unnecessary. A little simple math will do. Jack F (25176)
Jack F wrote: This is implied when you suggest matching the source impedance to the load. I am not confused. No. The model used for matching impedance is a non-ideal voltage source (ideal voltage source in series with source impedance) driving a load impedance. Current is (source voltage)/(source impedance + load impedance). Note that current increases as the source impedance gets smaller. That is the correct way to optimize the load impedance. Increasing current through a fixed load impedance will always increase the power without regard to source resistance. Yes. Matching the the load to the source is the optimum way to select a load impedance. I suggest you do the math then. With a non-ideal voltage source, you can optimize power transfer by selecting a matching load impedance. There is no corollary for selecting a source impedance. Ed (25197)
I copied a couple of your remarks here. "Increasing current through a fixed load impedance will always increase the power without regard to source resistance." This is Nonsense because the voltage must be increased for that to happen. "Yes. Matching the the load to the source is the optimum way to select a load impedance." Finally, a statement that isn't nonsense. But it contradicts your earlier position. I guess we are into a sort of contest now, and I really don't understand why you are trying to spin something so simple into a complicated idea. This isn't really going to accomplish anything, because you are looking for some special case that can never exist in order to prove some point. No matter how you slice it, a voltage source of zero impedance feeding through a resistance that simulates the internal resistance of a power source in the real world, the voltage will drop as current is drawn. When the amount of current drawn from this simulated source causes the voltage to drop to exactly half of the open circuit value, you will find that the load resistance is equal to the internal resistance of the source. At this point you are drawing all of the power that can be drawn from this source. Now changing any of the parameters in the source like the internal resistance results in a new and different source, so that would be cheating to win this argument. At that point further lowering of the load resistance will indeed cause the current to increase. However you will find that the voltage across the load has decreased and the voltage drop across the internal resistance has increased. At this point more power is being consumed inside the source than in the load. Doesn't this seem reasonable to you? If it doesn't, I can't think of any other way to explain it, and I give up. I will answer your one point, however. Increasing the load resistance to match the source impedance would indeed increase power transfer. I can't help but feel that you are so accustomed to working with very low impedance sources like an auto battery or a power line that you never have given any thought to source impedance, much less any need to match it for maximum power transfer. With a power line the source impedance is only a few ohms, mostly in the wire with the plug on the end of it, so of course you can draw much current with little voltage drop. As for selecting a source impedance to match the load, of course there is a ready example. It is why high horsepower motors are run on higher voltages like 240, or 240 3 phase, or even up to 480 3 phase. The Voltage/impedance ratio in the source is selected to match the load. Jack F (25198)
 
     
 

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