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Hi Charles,

Is my old Delco electric motor reversible?
There are four wires coming out of the motor (2 pairs) connected to 120V line voltage. One wire on each pair has a label and a color (blue & green). The other two wires are black. Other inscriptions on the face plate are, 8.1 amp, RPM 1725, 1/3 HP, 115V, 60 Cycles, Type SP, Code P. The motor is quite old and does not appear to have a visible capacitor. I have a similarly old Furnas Electric Co. Reversing Controller I would like to install if the motor direction can be reversed. From the information I provided you, can you tell if the motor is reversible? If so, how would I go about doing that?
Your assistance is appreciated.

I initially directed this question to Bill, but it looks like you are the expert in electric motors. Sorry for the duplication!


As I don't know which are the run and start leads, You can try this. Mark one pair as follows, black #1, the other lead #5. On the other pair, make black #4, and the other lead #8.

It will be this to begin. L1= 1&5.   L2= 4&8. Now swap #5 and #8. Then it will be like this. L1= 1&8, L2= 4&5. This should reverse your motor.  

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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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