Electric Power & Utilities/Popping capacitors


This is an old compressor with a Baldor Electric motor. Recently the motor would not start. We replaced all three capacitors. When we flip the breaker, the third capacitor will pop, blow smoke or leak oil, and the compressor no longer functions. We have looked at the wires on the motor and they are not bare. The electric motor series number 36075W8409, Frame# 184T, Ser.#F892, 5HP. The capacitors are 216-259 MFD capacitors.

This sounds like a shorted start winding. Start capacitors can only take voltage for a few seconds. If the motor cannot come up to speed, then the centrifugal switch cannot open the start windings. This motor needs to be taken to a repair center, where they can visually inspect the windings, and switch mechanism's. They can also make sure the capacitors are wired correctly. Sorry I could be of little help, but this one needs "hands on".

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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.

Former member EASA

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