I need help with motor wiring

Aug 1, 2000
A customer supplied a motor to mount onto a grinder, however the motor doesn't have a nameplate. It is a capacitor start TECF motor and has 4 wires. I've looked in my handy Electrical Engineering Pocket Handbook but I can not find a schematic for a 4 wire motor. The wires are clearly labled 1,2,3, and 4. Again, no nameplate, manufacturer, serial number....nothing.

Can any one tell me how to hook it up. Which combination for rotation direction and which combination for voltage...?

I appreciate it!



I think you have a dual speed motor - perhaps 1750 and 3400 rpm. What color are the wires? I have one at home that came out of a furnace - 1/3 hp with find red, white, green and black wires. On mine, I think green is GND, black may be common, and white/red control determine the speed. It may be that white is common, though too.

Sorta vague, sorry. Maybe someone can add?

Mike :confused:
That's the first thing I thought -- two speeds. I have one and I'll take a peek at the wiring to see if I can offer anything...
I found it!:)

I was walking through the shop and looked up and recognized the same motor hanging on the back of a JET drill press. This one had a nameplate and a hook-up schematic.

The motor turned out to be: 3/4 hp, 1725 rpm, 110/220V.

I'm all set!

Thank you all for the input!