View Full Version : Help please with Antique Motor!

08-28-2011, 01:59 PM
Gents, I got ebayed with an old motor purchase. The flaming f'tard that pulled the motor off the original equipment just cut the wires and didn't leaving the color lables in place. I guess I could just send the thing back, but I would rather fix myself if possible. Not least because my projects are being severely delayed by not having my lathe running.

THE WIRES ON THE MOTOR ARE NOT COLORED OR LABELED. One wire does have black insulation, but that's it.

The nameplate says the following:

1. Black is 1
2. Yellow is 3
3. Red is 2
4. Green is 4

The motor can be wired for 110 or 240. NOTE: THERE IS NO LABELING OR COLOR CODING ANYWHERE IN THE MOTOR. Just wanted to make that clear. It is a capacitor start motor.

The nameplate also says:

For 110

1. Connect Black and yellow (1 to 3), and hook to one side of 110.
2. Connect red and green (2 to 4), and hook to the other side of 110.

For 220

1. Hook black (1) to 220.
2. Connect yellow to red (2 to 3)
3. Connect green (4) to the other side of 220.

Here is the issue. If I assume the black insulated wire is black, then I think I can determine which one is yellow by continuity. HOWEVER, How do I determine which is "red" and which is "green"? If I swap red and green, what will happen? It'll run? It'll smoke? It'll sit and buzz from being out of phase? What do you suggest?

08-28-2011, 02:38 PM
There are two Run windings: The likely colors are Black -Red for one winding and and Yellow - Green for the other.

Verify the above by continuity check. The windings are connnected in parallel for 110V and series for 220V. Swapping Yellow and Green will produce a buzzer and no motor start as the two windings will be out of phase. Apparently the motor is non-reversible or there would be instructions for that. The start wnding must be internally connected and not accessible without motor disassembly which jives with the non-reversing assumption.


08-28-2011, 04:30 PM
That sounds like two run windings- they go in series for use on 220, and in parallel for use on 110. Either way you wire it, you need to phase them properly. To test, you would probably wire it up in parallel, being prepared to switch one set of wires around if it just hummed instead of running. Power it up through a resistance so you don't burn it on the spot. A high watt halogen worklight would probably make a good series resistance to test it with. Even if the motor can't come up to speed with the resistance in place, it will still tell you which way the wires should be. During the test, the halogen will light up- whichever wiring configuration lights it up the least is the way it should be. In other words, the less of a short it appears to be would be the right way.

I'm assuming the capacitor is a built-on and factory wired so you don't have to figure out which wires for that-

08-28-2011, 05:48 PM
So, I do have a risk of blowing the motor if I wire it up out of phase?

08-28-2011, 08:12 PM
Kind of. It will look like nearly a dead short- lots of amps will flow, then a breaker will pop. Not what I would recommend.

Any non-motorized appliance that normally draws a lot of current can be used as a limiting resistor- a 1500 watt heater for instance, or even a toaster. The hookup is pretty easy- a plug on a cord and two wall sockets temporarily wired all in series does the job. The heater plugs into one, the motor into the other, then the plug put into the wall. If the motor wants to turn, the wiring is correct. If all it wants to do is hum, reverse one set of wires.

08-30-2011, 05:43 PM
Thanks fellas' It's running. Now I just have to wrastle it into position!