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Need help wiring a 115v/230v cap start motor

4.7K views 4 replies 3 participants last post by  Nsjenner  
#1 ·
Looking for help wiring up an old GE motor. I have attached a picture of the name plate with the wiring diagrams and I'm trying to hook this motor up for 115v. The wiring diagram shows 4 posts and 4 leads. Problem is when I pull the cover off I can locate all the correct leads listed in the wiring diagram but there is a 5th wire that is yellow and labeled t4. Really not sure what this last wire is for and any insight would be greatly appreciated.

This motor definitely works and hooking up the wires as shown in the far left for thermal protection in 115v the motor will run but before I put the motor into service I want to make sure I won't fry something by having this wire left off.

Further information after checking with a meter.

Red (j10) has continuity with black (t5) and the capacitor
Orange (t3) has continuity with yellow (t4)
White (t2) has continuity with post 1 and post 2
Post 3 and post 4 don't seem to have continuity with anything
 

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#2 ·
A dual voltage motor like this will have the stator run winding split between two windings. When using the low voltage configuration they are run in parallel, when using high voltage they are run in series. T1-T2 form one winding, T3-T4 form the second. Since you're using the low voltage input T1 will be connected to T3, T2 to T4.

With T4 sitting loose only one half of the run winding is energized. The motor will start and run but will have limited available power output. Once a load is placed on it the motor will stall.

Remove the terminal board and look for a broken ring terminal or wire connection on terminal 4. T4 may have simply broken loose. Or someone may have cut it intentionally for troubleshooting. Was the motor in service and functioning before you got it?
 
#3 ·
That definitely makes sense but the lead labelling seems to be a bit different on the schematic. It's showing red ( j5 ) connected with orange ( t3 ) off one post and black ( t5 ) connected with white ( t2 ) off another post for 115v operation. This is an older motor so to access the back of the terminal board I'll have to pull off the front housing tomorrow but this won't be an issue. The yellow (t4) lead also was not broken off and has a ring terminal already on it.

I'm assuming Winding 1 is red (j10) with black (t5 ) and winding 2 is yellow (t4) with orange (t3) since they have continuity with each other.

The strange thing is that the white (t2 ) lead doesn't have continuity with anything but in the schematic it is being shown hooked together with black (t5) lead for 115v operation. It could be that the yellow (t4 ) is supposed to be hooked to the white lead in behind the terminal board since it is not even shown in the schematic but that's just a guess. Also the black (t5) and the red (j10) leads both have continuity with the capacitor.

I apologize if that all sounds confusing with the labelling of the leads but this is what's on the schematic on the motor.

The motor was running before I got it but was hooked up in a 230v configuration. I'll open it up tomorrow though and check out what's going on with the windings.

Thanks again.
 
#4 · (Edited)
Here's how it'll end up when you get done with everything......

For 115V and clockwise rotation looking at the back of the motor with the shaft pointing away from you, the incoming hot, blue, orange and black will be connected together. The incoming neutral will be connected to white, yellow and red.

To reverse rotation swap black and red.

Post 4 is internally connected to yellow.

Post 3 isn't internally connected to anything, it's just a splice point.

Post 2 is internally connected to blue and one side of the thermal.

Post 1 is the other side of the thermal.

There should be continuity (dead short) between post 1 and post 2. If there isn't, the thermal is bad.

There should be very low resistance from post 2 and white. If not, one of the run windings is burnt up or blue has become disconnected from post 2.

There should be very low resistance from post 4 to orange. If not then the other run winding is burnt up or yellow has become disconnected from post 4.

Black and red are the start winding. They will be an open circuit but read low resistance with the start capacitor jumped (shorted).

Rob.

P.S. On some motors, blue is brought out to the terminal box and connected to post 2. Yellow is brought out and connected to post 4.

Other motors have blue and/or yellow connected under the terminal board.
 
#5 ·
Thank you to both fishbulb and micromind for helping me get this sorted out. Motor works as it should now so now I can finish my project! Motor is going to be used on the custom built belt grinder below, plans were off the internet but I made a few modifications to make it a bit more robust. A 2"x72" grinding belt will go around the wheels.

Thanks again
 

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