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Electric Power & Utilities/Wiring a reversing switch to a 110V motor


Paul wrote at 2012-11-04 16:21:22
I have the same question. I have a reversable garage door motor (a.o. Smith F42a54a83   105.0038e) coming from the motor are: white, black, red &blue.

White connects directly to line (white) via block

Red & blue connect to a cap, then to where?

Black connects to where?

I've blown the fuse once, hoping to not do it again :)

Based on the second linked diagram, it appears I should connect a second white wire from the line block to the blue wire and the black from the line block (black) for one direction, then to change direction, connect the red wire to the white wire. Though it appears that I should connect both the red & blue to the white wire.

My logic is that closing the circuit with the blue/white will start the motor in one direction, and then switching to a red/white connection will start the motor in the other direction. Question... If that logic is right, then what does the other unused wire, be it blue or red connect to when the other is in use? My guess is that it connects to the other unused side of the switch when using the other directonl.

Perhaps I can make a diagram here



Red ------------ ?

White --------------- white (line)

Blue----------------white (line)

Black -------------- black (line)


Blue ------------ ?

White --------------- white (line)

Red ----------------white (line)

Black -------------- black (line)

And further clarification you can give, would be much appreciated


kensinner wrote at 2015-12-21 20:34:19
I also have an A.O. Smith F42A54A83 motor.

I have wired it up as follows, and it seems to run fine.  White to line (neutral), black unused, blue and red to motor cap., hot wire to cap. terminal with blue or red wire depending on which way you want it to rotate.

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Charles C. Jones


Let Me help you with your problems with single phase and three phase electric motors. I can tell you how to troubleshoot your motor problems. From simple testing of capacitors, how to test your windings, replacing bearings, and general maintenance. Before we go any further, remember these words of advice: Disconnect the power before you do anything! Please limit your questions to electric motors and there immediate components. I review each question, and if I can answer or help, then I will. If you receive a rejection, it means it is out of my expertise, and just do not have the answer. I'll be waiting for your question.


I have 40 years experience in the repair of electric motors and related equipment. I am a master machinist in the field of motor repair. I was employed with my company for 35 years, but retired in May of 2013. The downside to that is I lost access to a lot of technical data. I will still try to give you the most accurate advice that I can.

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