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Wiring single phase motor for reverse

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wsemajb

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There is another thread on this, but I did not find sufficient info there.

I've got two motors that are now running CCW (facing the shaft). They are both capacitor start, single phase, one hp, motors. Both have a single capacitor attached and audible click on/off centrifugal switch. Both are wired for 120v. However both of them only have four terminals.

The first one has four marked, clockwise from the bottom, L2, 4, 2, and COM. LO appears between 4 and 2. Otherwise the motor is lacking any other placards or markings.


The second has terminals marked, from bottom, simply 1, 2 ,3, nd 4. AC in was connected to 1 and 4. I tried swapping the leads on 2 and 4 to no avail. Motor did not even run.


There is a placard on this one.


I cannot find any information on these motors online. Can anyone suggest how to reverse direction on them? I think the first motor was actually reversed at some time in the past, but I did not write down how to do it. This time I'll scratch in somewhere.

The second one may be another case. I wonder if it's possible to get inside and measure for the starter winding and reverse the leads on the one with highest resistance. I've read about this, but am not clear what is meant exactly by "reversing" them. If I can follow the leads off of the start capacitor into the frame won't this indicate the starter winding?

Thanks for any suggestions.
 
Last edited:

MikeMl

Well-Known Member
Most Helpful Member
I have no info about your specific motors.

Here is the how the motors are likely wired internally. Note that I labeled the four terminals A-D, just for discussion. With an Ohmmeter, you should be able to figure out which lead is which. Note that in my diagram, there is a steady DC resistance between terminals A-B, but that an Ohmmeter will see a charging capacitor between C-D (the switch is closed, the Start winding is a low resistance).

Once you identify the pairs A-B and C-D, then it is a simple matter to connect L1 to A and C, L2 to B and D for one rotation, and L1 to A and D, L2 to B and C for the other rotation.
 

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