Lathe - Motor - Wiring



Electrical wiring protection (Sep 22, 2002) Motor wiring? (Apr 19, 2004)
3 phase schematic (Jan 27, 2003) Identifying Motor Leads (Jul 6, 2004)
Wiring for SouthBend (Feb 12, 2003) Wiring Question (Oct 17, 2004)
Two speed motor wiring (Mar 1, 2003) Rewire for 1hp 110v (Jan 3, 2005)
Motor wiring (Jul 14, 2003) Motor Wiring SB9A 1/2HP Motor (Feb 2, 2005)
Motor Wiring (Aug 16, 2003) More wiring tips (Feb 4, 2005)
Help wiring a motor 230/460 3 phase (Dec 8, 2003) Big mess of wires (Feb 24, 2005)
Electrical wiring protection
There are good and bad things about using a series device. if there is a dead short you know it pronto. helps to make that enie-meanie-miney-moe decision just a little more safe. this is only a low power test device. my $0.02 Dave general technique. I don't like series resistance as much for motor testing, since it can prevent the motor from starting. My experience is that it is pretty hard to damage a motor with the voltage it was designed to run on (i.e. 110V on a known, 110V motor) if the voltage is only applied for a few seconds, since the damage mechanisms are thermal, and the thermal masses are generally large (i.e. it takes longer for the magic smoke to escape). (6419)
3 phase schematic
I wonder if anybody has a wiring diagram showing the hookup for using a 3 phase motor (220 Volt) as a slave unit to drive the other 3 phase motors? (8950)
Bob Swinney and Fitch Williams are the most knowledgeable people I've bumped into on rotary phase convertors. They hang out pretty regularly on rec.crafts.metalwork (newsgroup). Once you have a design you might ask on rcm for them to take a look. Useful links: http://www.metalwebnews.com/howto/ph-conv/ph-conv.html  http://www.dogpatch.com/bobp/3phase/  http://www.homemetalshopclub.org/projects/phconv/phconv.html  For what is worth, I'm still using my idler without tuning, though I mean to tune it in the near future. If you don't mind starting with a pull rope, you can just wire the single phase source to any pair of leads on the idler, and run feed to the 3-phase box from all three leads on the idler. Some folks start their idlers with a pony motor instead of with a starting capacitor. Adam (8951)
I built one based on the designs found on the metalwork newsgroup, and got the capacitor sizes pretty close on the first try. I mounted it in a nice size wall box, with a 220v single phase feed in. For the outlets, I mounted 220 single phase and 220 three phase outlets one either side of the box (different plugs to keep separate). For the three phase, I used three wire plus ground plugs and used matching range or dryer cords on the machines. I can then use my large lathe motor as an idler by simply starting the lathe first with the belt loose, then the other machine as needed. As an aside, unless I am stupid, the South Bend had no grounding connection. It appeared to depend on the presence of a conduit connection for the ground. This seemed incredibly dangerous. Be sure you are grounded! (8955)
You want to build a 220V 1 phase to 220V 3 ph rotary convertor Here are two versions. The convertor motor must be larger than the others. Rich (8956)
Wiring for SouthBend
I put a single-phase motor in my lathe in place of the three-phase that was in it to simplify things (no three-phase in my shop). What have I gotten myself into as far as the wiring up to the motor (i.e. The fuse/switch box on the machine has three termination points, which leads to a box with relays for the push switches- forward/reverse/stop)? Will single- phase require a dramatically different wiring scheme from three- phase? So much for simplifying things, huh? Noah (9272)
First thing you need to decide is whether you need reverse. If you don't need reverse you can start the single phase motor with a snap switch. (looks like a heavy light switch) also known as a manual starter. If you need reverse, you can either rewire the existing starters (relays) to reverse the single phase motor, or install a reversing manual starter, also known as a drum switch. Wiring diagrams for this sort of thing are available from motor control manufacturers like Square D. RC (9275)
Unless you already have the single-phase motor you have two simple methods for running your existing 3 phase motor. The traditional way is to use a static phase converter but the method I would generally recommend now is to use a Variable Frequency Drive, not only will this give you three phase for the motor but also speed control at the turn of a knob. The range of control using VFD's is from no movement to about 6 times normal RPM, (not recommended for normal motors). Typical costs for a two HP machine are $140 for a static and $300 for a VFD. If you continue with the single phase motor, it is necessary to get to the internals of the motor if you need to reverse. Bernard (9277)
Noah, To answer your question: Yes, converting the control box for the motor from 3 phase to 1 phase will be dramatic (or at least involved). I bet they are Furnas brand. Most of the SBL's I see come with them. But it doesn't matter. Most all contactors/magnetic motor starters functionally work the same way. First, let's talk about the motor. I hope the motor you have chosen is at least 1/2 Horse Power (HP) and is a capacitor start motor (in most cases, it will have a metal "can" mounted on the top where the capacitor will be stored). This kind of motor has a high starting torque needed for overcoming the inertia of the lathe's moving parts. Next you will have to identify the leads in the motor. How many leads does it have and are they numbered? Some older motors will have a circuit board with terminals. The number of leads will depend on whether your motor is a dual voltage motor and whether it is reversible. The leads or terminals should be identified on either the underside of the access plate to the leads or on the identification plate on the side of the motor. While your at it, check to see if your motor has "thermal overload protection" built in to it. Collect this information and report back and we'll tell you how to proceed. Also, look inside the enclosure for the contactors/motor starters. the underside of the cover should have a wiring diagram for your control box. At this point, check the transformer input voltages and the voltage for the coils on the contactors. Most of these 3 phase units will work on 230 or 460 volts. Some are set-up for both single and three phase operation but if yours is not, don't despair yet. This post is getting too long. So, collect the following information and get back to us and we'll go from there: From the Motor: ------ Type of Motor, Motor Leads Numbers, Motor Voltages, Whether The Motor Is Reversible, Is the Motor Thermally Protected, From the Control Box: ---------- Transformer Input Voltage, Contactor Coil Voltage, With this information, we'll be better able to help. Webb (9279)
Two speed motor wiring
I just got my 1970s Heavy Ten Toolroom lathe back together after having South Bend regrind the ways and having the saddle scraped in ( looks like brand new now). All the slides scraped and all bearings and gears cleaned, inspected and are in great condition. The problem is it came with a two speed motor and two sets of push buttons that is wired to a 220 volt 3 phase box with 5 wires. The red, black and blue go to the fuse terminals and the bare ground is grounded all around. The problem is the fifth white wire, not fused goes to another connection in the box. My guess is this is a neutral wire that goes back to my shop power box. Or since a 110 volt light and outlet is on it also is it needed for that or a control system for the two speed motor. Walt (9558)
If I understand you correctly, the four wires in question are the inputs from your service (fuse/breaker box) to the motor starter box. As you surmised, the red, black and blue are the 3 phase inputs to the motor and the white is the neutral for the 110,115,120 (what ever) volt system on your lathe. You can check the white (neutral) with an ohm meter for continuity between the lead and the outlet box/light on your lathe. The control wires for the two speed motor should be between the motor starter and the motor itself. Webb (9559)
Webb, I checked and the white wire is a neutral for the 110 volt light and outlet. Walt (9570)
Motor wiring
I just bought a new lathe, wired for 220, its a Baldor 3/4 hp 115 /220. How to I change from 220 to 110. I pulled the plate on the motor off and was hoping there was a diagram, but no luck. There are six white wires, and one brown wire coming from inside motor. Two of them are connected together, the others are going to the switch. The brown is taped off and doesn't do anything. (12697)
Put tape on each wire and number them. -record the present connections. -separate all the wires. -with an ohm-meter, test pairs of wires until you find each coil. -record the ohms of each coil. -the run coils will have very low values and equal. -the start coil will be much higher or as below. -assuming this motor has a start winding and centrifugal cutout switch, this motor has 2 run windings and one start winding. -if capacitor start, the start winding will have the cap in series with the start winding and switch. The ohm meter will only give a kick or momentary reading. -the other two coils are run windings and are connected in series for 220VAC and parallel for 120VAC. -so, you may find that the original connections were indeed two coils in series. -reconnect as before temporarily -find the center connection of the two run coils and separate. -make one coil A, the other B. Each end is A1 and A2, B1 and B2. -now connected as: power A1..coil..A2 -reconnect as: power A1 -now you have them connected in parallel for 120VAC. -if you mistakenly connected the two run windings backwards (apposing), the motor will hum and not spin. -the start winding may be connected only across one coil as it is rated at 120VAC only. So, this remains the same. -test by quickly applying power momentarily. It should spin up to speed instantly. -the start winding will overheat very quickly if the motor does not spin up to full speed and allow the switch to kick it out. Richd (12698)
Does the nameplate list both 110 and 220? There are some voltage specific motors. Dave (12700)
Go to Baldor's website and ask them. Bob PS: Baldor probably makes the best elect motors in this country. (12703)
Motor Wiring
I recently purchased a 9" model A. The motor turns clockwise when the switch is in the forward position, this doesn't seem right, am I wrong? If someone has the wiring diagram I would appreciate it. I assume the motor is 110 single phase. Fritz (13390)
If their motor is mounted normally, pulley on the left, then the lathe chuck will turn top toward you. That's CCW looking at the face of the chuck. This is the normal lathe direction for turning (machining) material. RichD (13391)
Earlier today I uploaded the wiring diagram from the Furnas Drum switch that came with my 9. It's in the files section. In general, a single phase motor is reversed by reversing the power feed to the wires to ONE of the coils. If yours is running in reverse, then reversing one of the coils should change that to forward (that's what the reversing switch does). Some motors have more than three coils so be sure you are changing the correct one. Look for the coil that the switch reverses and reverse the leads. Paul A.  (13535)
Paul all, there are several versions of that drum switch. All that I have can be configured for FHP motors. See the interior case diagram. I have R4, RSB4, R44, R324. These are the old all metal case units with the red ball handle. RichD (13536)
Help wiring a motor 230/460 3 phase
I have a heavy 10 sb lathe with a reliance 230/460 1 hp 3 phase motor and the wiring diagram is missing it isn't wired up at the moment. I want to wire it 230 3 phase. fred (15437)
Starting from first principles is tricky but haw many wires do you have (6?) and what are the colors? Jim B. (15438)
Most small horse power motors are Wye wound. Assuming it is (over 95% are), you should have nine leads coming out of the motor (most dual voltage three phase Wye motors do). They should have numbers on them (T1 through T9). For low voltage (208-230V) connection: Phase A T4 + T5 + T6. If your motor has a different number of leads, or is the rare exception and is a Delta wound, The connection will be different. To test your motor to see if it is Wye or Delta wound, you will need an ohm meter (or continuity checker). A Wye motor will have continuity between: T1 and T4, T2 and T5, T3 and T6, T7 and T8 and T9. A nine lead Delta wound motor will have continuity between: T1 and T4 and T9, T2 and T5 and T7, T3 and T6 and T8. Webb (15439)
Jim, the motor has 9 wires and they are all black and labeled t1 - t9. fred (15440)
Motor wiring?
The motor I have on my lathe is a GE type kc 4 wire capacitor start . the wiring diagram has long disappeared. Can I wire this motor to be reversible? (18513)
The short answer is Yes. For one direction the two winding (start winding with capacitor in series and a run winding) are connected in parallel. To reverse connect the two windings in parallel but reverse one windings. You can find the individual windings by using an ohmmeter or other continuity checker. Ted (18516)
Identifying Motor Leads
I recently got a 9" Junior lathe with a 1/2 hp, 115v capacitor start motor with 6 leads. I am attempting to wire it to a drum switch but can't tell how to wire it because the color braiding on the wires is faded and stained. Can anyone tell me how to identify the leads and how they would be wired to the drum switch? Of the 6 leads, 4 were in pairs, the remaining two are individual. Anyone know of a website that might have the lead identification procedure? Fred (19919)
Pretty good diagrams here. http://shop.emotorstore.com/estore/TD_Schematic_Diagrams.asp  Jim B (19922)
A little more info. Chances are the two loose leads are the start leads S1 and S2 you can verify this as they should not be electrically connected to any other lead at all. That leaves you with the 2 pairs. Call them A B and C D. Im guessing that when you hook the 2 pairs up to 115v the motor should go in 1 direction. To change the direction you will need to swap B D as well as the 2 s1,s2 leads. That should help narrow it down further. So i think you can get it going 1 direction for sure and you have a 1 in 4 chance of reversing it right the first time. (19923)
Switch 5 and 8. As far as identifying them not sure. Jeff (19924)
Jim, I did find this site on the web. Any idea on how to identify which lead is which, I have no color code to guide me. Fred (19925)
Do you have a multi-meter? You said 6 wires, two groups in pairs and two by themselves. My guess, and its just a guess, is that you have a dual voltage motor. Does the name plate specify 120 or does it say 120/240 (perhaps 110/220)? With a multimeter you can determine that: 1) there is a group of two wires (I would guess the odd pair) that does not have continuity. (look at the second picture down on the left, T5 and T6. 2) There will be two groups which have continuity to them selves, These would be T1, T2 and T3, T4. What we don't know is which is T1, and which is T3. For 120 T1 is probably connected to T3 and T2 is connected to T4. Reversing the sense of T5 and T6 would reverse the motor rotation. Reversing the sense of (say ) T3/T4 would cancel the field and cause the motor to not rotate well. You could brut-force it, take a guess, wire and see if it runs. If it hums and doesn't run you need to reverse one pair. (I DON'T RECOMMEND THIS). The T1/T2 to T3/T4 windings will act as a transformer. I you had another transformer, low voltage, say 12V or lower, perhaps a bell transformer, you could connect it to T1/T2 Then connect any lead from the other stator winding to (say) T1. With an AC volt meter read from T2 to what you now suspect is T4. If the winding you connected to T1 is, in truth, T3 you should measure a very low voltage. Perhaps not zero, but no more than a few volts. If its actually T4 connected to T1 they you will measure close to 24 Volts because the windings are connected in series. You want the condition where the voltage is low. This should be set up so you can plug the transformer in quickly on read the meter and then unplug it. The windings may draw substantial current without the motor turning. If you don't have a multimeter let me know and I will try to figure something else. Again, first ring out the windings, then determine the proper AC polarity. Perhaps you could tell me what the wiring diagram states. Jim B. (19927)
Jeff, It turned out OK. Starting with the pairs was a big help. As it turned out, I just needed to swap the S1 and S2 leads, and it worked fine in either direction. I followed the 6 lead dual voltage - lower voltage diagram on this site from Siemens: http://www.sea.siemens.com/contrlbu/upld/files/p41-46.pdf . Funny how after it is running it seems so simple. Fred (19944)
Wiring Question
I am installing a new motor on my heavy ten and am having a rough time finding a wiring diagram. I have a GE F15E1 motor (110 or 220V reversible single phase motor) and the standard Cutler-Hammer Size "O" drum controller. GE might have a wiring diagram (website shows how to download it) but all that I am getting are VAX server communication errors. Anyone know of a good resource for this? Mike (21379)
Try this: http://shop.emotorstore.com/estore/TD_Schematic_Diagrams.asp?  Siemens has some good diagrams too. (21395)
Rewire for 1hp 110v
What do you guys think about these motors? http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=41376  http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42150  http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=47025  What is the difference in the three above motors? I don't understand what the different ratings mean...COMPRESSOR DUTY, AGRICULTURAL/FARM, TOOL/WOODWORKING...etc. The only one that says that it is reversible is the the first one. But I wonder if the "1HP" rating is a load rating or a "peek" reading? If you have any other suggestions for a NEW motor (other than ebay) let me know. I have bad experiences with trying to find a good reversible motor on ebay. I would just rather not bother. (23692)
Anything that has the name Chicago electric on it (harbor freights house brand) Is scary in my opinion. I have seen some of the power tools that carry that name, some don't even use bearings! Try this site for a real motor. http://www.electricmotorwarehouse.com/  Jeff  (23693)
The compressor rated motor also says it is reversible, plus it is TEFC (totally enclosed fan cooled) meaning there are no openings in the case for sawdust or metal particles or grinding dust to get inside. That is a good thing for a lathe. But, it does not say it is instantly reversible, which is a very desirable thing for a lathe. I had one that was reversible but not instantly, and I accidentally flipped the switch while it was running and the whole thing blew up with a loud pop! I replaced it with a HF (I can't remember which one) and it ran fine as long as I had that lathe. I put the reversing switch down on the motor so I wouldn't be able to reverse it easily or quickly. These would seem to be real HP since at 230 volts the current draw is 8 Amps. Another good source of motors is Grainger, but they are a little pricier than HF. Grainger does have instant reversing motors. Look at http://www.grainger.com/Grainger/wwg/catalogPDF.shtml  page 72.The prices in their catalog are list price, and they only sell wholesale, but if you can buy it for your "work" (employer) but then pay with your personal credit card you can get a substantial discount. Or if you have a home business with some official looking business cards (and you might need to show them a resale license if its a home business). Neal (23694)
The TEFC compressor unit looks like the best bet- the farm duty looks a bit chintzy. The "machine" motor doesn't reverse and isn't enclosed. While I have had good luck with HF stuff, others have had issues. Our local Fleet Farm sells Marathon motors for a reasonable price- around 130 for a "US-built" 1hp TEFC. Grainger is usually a bit higher for the Dayton brand. We used these a lot on special machinery with no issues but that was 20 years ago. Instant reverse is nice but not a big deal, in my opinion. This is especially true if you have a threaded spindle- instantly reversing could have your chuck spinning across the shop floor. Thermal protection is nice. 1 hp may or may not work on 110V 15 amp. The starting current is will be at or above the max amperage. A 20 amp is better but I would recommend either going 220 or with a smaller motor. Anyone have different experience? While some hp ratings are often exaggerated, volts and amps don't lie. A 110V 1hp motor runs at around 8 amps and uses about 13-15 amps on startup. Most motors are pretty efficient now days so to that use the same amps should give about the same output. Bill (23695)
Is the phase convertor listed at this sight any good or not $158 up what else would be needed? Thomas (23696)
No it isn't! Instant reversal can put too much strain on everything including (as you found out) the motor. An "instant" reversal could also easily cause the thread mounted chucks to unscrew. Peter (23697)
TEFC (totally enclosed fan cooled) meaning there are no openings in the case for sawdust or metal particles or grinding dust to get inside. That is a good thing for a lathe. But, it does not say it is instantly reversible, which is a very desirable thing for a lathe. I had one that was reversible but not instantly, and I accidentally flipped the switch while it was running and the whole thing blew up with a loud pop! I replaced it with a HF (I can't remember which one) and it ran fine as long as I had that lathe. I put the reversing switch down on the motor so I wouldn't be able to reverse it easily or quickly. These would seem to be real HP since at 230 volts the current draw is 8 Amps. What is the benefit of instant reversing other than to test the change gears ? It seems that an electrical brake would put serious pressures on the few engaged teeth and instant reverse would put even more pressure on them. I can't remember a time when I used an instant reverse. Am I missing some benefit? Dave (23712)
Compressor motors generally run at 3450RPM. Lathes typically use 1725RPM motors. (23713)
Grizzly offers the best deal on motors that I found. $100.00 gets a 3/4 hp open motor delivered. Griz also offers motors in both speed ranges. http://www.grizzly.com  Open drip proof is open and has an internal fan that blows air thru the motor innards. that is air and dust... My open motor gets swarf dumped in it and two years ago when I first fired it up, I swore that at the first spark it would be replaced. Still waiting. Personally I would prefer a TEFC, Totally Enclosed Fan Cooled or TEAO totally enclosed air over. same thing. There is a fan on the end of the shaft and it blows air over the motor for cooling. This work at full speed and not with a variable speed drive at greatly reduced speeds. Harbor Freight motors are NOT UL unless they are specifically listed as UL motors. A good thing to pay extra for. As for descriptions, I have not found a reliable listing, but farm duty motors are often listed as having gasketed and sealed connections like sealed bearings, gasketed and sealed capacitor box. gasketed electrical connection. Not rain or water tight, but I think insect tight. I think for outdoor use, but not all-weather use. There is a more important number and that is service factor. 1x is common, 1.25 is better. IF the motor is out of the chip stream, go with open as it will keep cool better. if it is directly in the chip path, use TEFC or add a sheet metal shroud to keep the chips off AND allow for air to cool. Dave (23714)
Well two things really. The first is, like I said, on a non instant reverse if you flip the switch by accident you can blow something up. Secondly, if you should ever have the misfortune of getting something accidentally wrapped around the work and the lathe is sucking it (or you) in it is a good thing to be able to back it off really quickly. Regarding stress on the change gears, true it will put some stress on the gear train. True the spindle still has momentum when you throw the switch, but the motor doesn't actually instantly reverse, it decelerates and then accelerates in the other direction. Granted, it does that pretty quickly. But, I don't think the force on the gears is that much greater than when you throw the switch into forward. These lathe motors don't have soft start so they accelerate the spindle up to speed as fast as they can. A good point was raised about the chuck possibly flying off during reversal. I hadn't thought of that. (23741)
Jeff, I have a HF Chicago Electric 1HP in my lathe. Curiously, it is made in the USA. In any case it works fine and has ball bearings. The original poster didn't say what the size lathe size is or what the drive configuration is. If the motor is exposed to swarf (should be obvious from inspecting the old motor) then he may want a TEFC motor. Otherwise the first motor would be fine. If the lathe already has a 3PH motor and he has 220V available, I would go for a VFD off ebay for about the same price as a new motor. Ed (23775)
I just found a 3/4 hp 3phase motor in the back. looks nice and clean. It may be too big to put on my lathe, but in my search for a new motor, it seems that one is hard pressed to find a decent motor for less than $100.00 and the vfd option makes $100 look cheap. Btw, if you are half decent with re-wiring a single phase motor into a reversible one, you can buy the HF band saw replacement motor for about $38.35. 1 hp. If anyone is interested in that, let me know and I'll fwd my e-mail from tech support with the price. Dave (23778)
Dave, That price is for an import, non UL and it probably has a limited life expectancy. You are correct on the motor VFD prices but here is another item where new price reflects quality. On a 10L the motor is mounted underneath and a PIA to change. Its a 56 frame motor. The single phase capacitor start reversible motors are the most common ones available. Compressor duty means it has a high starting torque so it can start under load. Single phase motors need to be stopped before reversing or the starting caps can explode. 3 phase motors can be hammered on all day with minimum of problems, not single phase ones. Motors cost a bit to ship due to their weight so figure that in when deciding what to purchase. Some discount places like Northern tool and Harbor freight inflate the shipping costs to make the sell price look good. See if there any local motor rewind shops that might have a used motor in good shape for sale. You may get a deal, especially after figuring in shipping cost. JP (23779)
In a capacitor start motor the capacitor feeds an independent start winding through a centrifugal switch. The combination of the capacitive and inductive reactance provides a current in this winding which is out of phase by approximately 90 degrees with the main winding and allows the motor to start. When the motor reaches some speed the winding and capacitor are electrically disconnected by the switch. This is why the motor cannot be reversed until it comes to a stop. Since the capacitor is not it the circuit it could not explode. Reversing the switch allows the motor to keep running in the same direction. As the motor slows down the centrifugal switch stays in the open position to a much lower speed than is required to open it. There is a very narrow range of speed where the motor is still turning and where the centrifugal switch is closed where it would be possible to reverse the motor while it is turning. One would need to shut the power off, weight until you heard the switch close an then reverse it. Under these conditions the current in the capacitor might overload. But you would need to work at it. Jim B. (23780)
Jim, What you describe is how I understood reversible motors to work. But on my old Seneca Falls lathe it had a reversing toggle switch and one day I flipped it by mistake instead of the off switch. Something, if my memory serves me it was the reversing switch itself, blew up with a loud pop. After much cursing and self-deprecating self-talk, I ended up replacing the motor with a HF cheapie. But, I am still trying to figure out why it blew up. Any ideas? Also, my South Bend has an instant reversing motor. It seems to me that it is a capacitor run motor since there is no sound of the centrifugal switch kicking out, and it is instantly reversible. Is that how this is achieved? Neal (23798)
Neal, I can't answer your question on why your switch burned out but I can shed some light on how an instant reversing single phase motor works. There are a couple pf ways this is done but the system I am most familiar with uses a relay inside the motor connected to the start windings and the centrifugal switch. The old GE motors used on SBL's that were instant reversing were not capacitor run motors. To put it as simply as I can, the interplay between the centrifugal start switch and the relay allows the start windings to be used as a magnetic brake to rapidly slow the RPM of the motor down until the centrifugal switch contacts close, bringing the starting capacitor back into play and reversing the motor's rotation. This type of motor has windings designed for this extra load. Otherwise it would be very hard on the start windings. Webb (23803)
I would need to know more. Was it a capacitor motor or an induction repulsion. What was the "reversing" switch like? dpdt?, center off? Webb Wyman answered "Part B" There are several posts about these "Instant reversing" motors in the archives. There are some times when the standard descriptions seem to be less than accurate. For years I believed that there should be no difference in starting torque for a motor wired for 120 or 240 V. There have been several published tests to substantiate this. However on a cold day my (2 HP HF motor) air compressor (Home built/assembled) would stall on 120. ( #12 wire 20 amp line) I rewired to 240 (30 amp #10 line) and it no longer stalls. (Voltage drop in the line?) Jim B. (23807)
Motor Wiring SB9A 1/2HP Motor
I acquired a South Bend 9" model A recently. The motor's wiring to the machine and to the power outlet is in poor shape and needs replacing. The thing is I have no idea what kind of wire to use? Pat (24668)
I believe you are talking about the cord from the motor to the wall socket. For a 9" the motor should be less than 1 HP. This would put the amperage draw at about 9 amps, even allowing for some higher current on start up, #14 wire could be used. Be sure to use 3 conductor. The green wire should be ground. Connected to the round pin on the wall plug and to a lug inside the motor wiring box. I have found that it is usually less expensive to buy a short extension cord (grounding type) and cut off the socket end and use the rest as the cord, unless the plug you have is OK. Jim B. (24679)
Listen to Jim. He talked me through rewiring my 9A motor switch. David (24684)
I used solid copper 12 ga for power and 14 ga for control. This is with a magnetic start 220 1ph 1hp motor. 14 ga would have been fine. You may be able to go one size smaller with stranded wire. I should have used stranded wire since it is more vibration/movement resistant. However, I have a cabinet full of solid wire from old house projects and feel comfortable that it will survive the low hours I will put on the lathe. Connections are much easier too. I always solder on stranded wire terminals- I've seen too many crimp-ons where installation has cut half the strands. With stranded wire, you should also use heat shrink tubing to strain relieve the crimp area. With solid you just stuff it under the screw (form a hook if there isn't one of those square grabber pads) and you are good to go. One more caveat- I don't know whether solid wire in a machine would meet code. Is there a code for a private use machine? It isn't a permanent house fixture so I don't think those rules apply. Good luck, Bill PS- with 110- black is hot, white is neutral, and green or bare is ground. If you look in the main box, all of the neutral and ground wires hook to the same place. Again- this is 110, not 220 or 3ph. (24705)
Try McMaster-Carr. They have molded power cords that will work. Check out pp. 728 on their website: http://www.mcmaster.com/  Webb (24710)
Thank you all for the info. The motor was wired with solid copper wires but they were in bad condition and there was no ground also. I'll let you know how I do rewiring it, hopefully without zapping myself in the process. Pat (24722)
More wiring tips
Someone mentioned buying a molded cord from McMaster. I went to Menards and bought the heaviest duty extension cord I could find on sale, cut the female end off, and had an instant 110V pigtail. In the end, I cut the molded 110 plug off and went to 220V- the motor didn't run and I assumed the issue was wiring. Turned out to be the starter cap switch but I left it 220. Inside the motor, I solder on the full circle connector ends and use brass screws to connect things. This way you don't damage the wire every time you connect/disconnect like you would with wire nuts. This habit started back in my special machinery days- the motors we got from Graingers came with eye lugs and, once we saw how they made trial assembly easier, we stuck with them. At times I've tried terminal strips but most motors don't have enough room and you really can't insulate them. Arrange the connection as a "pigtail"- all of the wires coming in from one direction. Once the screw/nut/lock washer is tight, use side cutters to cut the screw short and use plenty of electrician's tape- the thicker rubber stuff with a vinyl final wrap works best. A wire tie around the wires can shield the screw from torque. 6-32 works fine but 8-32 is better. I've always used brass. Belt and suspender types can use solder flux during assembly then hit the screw with an iron- solder will suck in and hold things together. Some years back, the Mexican government was complaining about how we were shooting all the crows. Apparently they migrate, much like ducks. To them, crows serve a vital function keeping the roads clean while ducks are considered flying rats. The US instituted a crow season with limits. Outside the season, you can only shoot a crow if it is causing damage or "about to cause damage." Funny how you can see that malicious twinkle in a crow's eye- even at 300 yards through a high power scope. Similar approach for other "carrion?" Bill (24751)
Another tip: I found trailer lighting cable (from tow vehicle to trailer I mean) to be a good way to use several different colored wires yet still have them bound within the one external sheath. Len (24752)
Big mess of wires
I need to redo the wires on the motor for my SB9 Model A. I bought a soldering gun so I could do a proper job. But I am lost. The thing is, there was no ground before. So I want to put one but I am supposed to run the ground to the motor and the power goes to the lathe. So I can't have my 3 wires going directly to the lathe. Should I run 1 wire as ground to the motor and the 2 for power to the lathe? Seems weird for some reason? Anyway, English not being my first language, I just thought I'd try and put all this big ole mess on a picture/drawing to see if one of you gentlemen can shed some light here. In the corner is the diagram of the electrical box on the lathe with the numbers that were on the wires. The wires for the lathe are solid copper which I think I will leave but I wanted to put a new shielded wire for the power and ground. (You can see it in the pic with wires A,B,C). http://www.armurerieduroi.com/lathe_wires2.jpg  Pat (25532)
If you are running the grounded (3-wire) power cord to the switch, connect the ground wire to the switch box at one of the screws mounting it to the lathe and another wire from that same point to the motor. Both the switch box and the motor should be grounded. Roy (25535)
1 The switch must be included in the wiring arrangement. I see a reversing type master switch in your pix. but it is not the usual Cutler Hammer (looks like a Furnas). 2 Power and ground must be taken to the switch first and then continued to the motor. At the motor, ideally the ground should be attached to a screw used for no other purpose, but at time your motor was made it was acceptable to bring the ground wire back out of the terminal box through the "U" recess (I can see one in your photo) and then connect using a cover screw). 3 I can help you with the rest of the wiring but will need complete details from the switch and the motor. Jim (25544)
Roy, that seems so simple now that you say it. Pat (25549)
I see a reversing type master switch in your pix. but it is not the usual Cutler Hammer (looks like a Furnas). continued to the motor. At the motor, ideally the ground should be attached to a screw used for no other purpose, but at time your motor was made it was acceptable to bring the ground wire back out of the terminal box through the "U" recess (I can see one in your photo) and then connect using a cover screw). complete details from the switch and the motor. Thanks Jim, what details do you need? I don't know much about this so I don't know what you need? Pat (25550)
1 From the motor nameplate (if it has one) indicate Manufacturer, and supply voltage (120 only) or (120/240) 2 Is there any marking on the terminal board, or does your marking reflect the Mfrs marking. 3 Is there a nameplate on the switch. Can you include a close-up photo. Or list the details. Jim (25553)
Here are the pics. Not sure about the terminal board. pic1  pic2  pic3  pic4 pic5 pic6  If it's not clear on the pic, the motor is 110/220. Pat (25555)
Pat, I'm a bit late on this post. Hopefully a few comments might help. For this type of job I would recommend you get a cable crimp kit, besides the crimpers themselves you get a selection of ring and spade terminals to fit the different size wires and terminals you will encounter. There is also a selection of in-line crimp connectors. Solid copper wire is not the easiest to work with, multi strand wire is electrically just as good, but is much easier to work. I looked at the motor nameplate and also the switch wiring diagrams, the motor doesn't directly correspond to either, however that shouldn't present any problems as long as you marked the wires before you took them off. The wiring diagram shows that one of the ac lines, line L2. goes to the switch and motor, the other line goes only to the switch, and will be internally routed in there to go to the motor. The ground line you want to install goes directly to a terminal on the switch, which should be marked with a ground sign; make a new wire, with a ring terminal at each end, connect one end to the ground terminal on the switch, the other end connects to the motor, to a ground terminal if one is marked, otherwise to the screw holding the cover plate. When you say you want to put a shielded wire for the power and ground, what you need here is flexible conduit, there are screw ends available for the hole sizes in your switch box and motor. Bernard R (25624)
1 Your motor has two independent windings, one of which is the "run winding" and because it is for use with a single phase supply your motor also has a "start winding". 2 To accommodate dual voltage (120/240) the run winding is in two equal parts which can be connected in series for operation on 240V, or in parallel for 120V. 3 Although the start winding is sometimes connected like the run winding for operation on dual voltage, it is frequently as a 120V winding and tapped off the run winding, using that winding like an autotransformer. This complicates a verbal explanation, but we will assume a tapped 120V type as it is the most likely. 4 As an aid to identification, the start winding is rated for short time operation and is wound with smaller gauge wire than the run winding. The start winding is also connected in series with a normally closed, centrifugal switch which opens the start circuit once a certain RPM has been reached and will remain open at any speed above its setting. The run winding may have a thermal switch in series with it. 5a One of the four terminals of the run winding is identified as T1 (or blue when color coded) You have a blue wire. The other end of that half winding is T2 (white) You have a white wire. (25630)

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