Reverse Rotation Method to Break Locked Rotor

■     Turn off power and remove the wiring from the hermetic compressor motor terminals.
■     Study Fig. 3-15.
■     Wire line one to common and line two to start. Use rated compressor line voltage.
■     Attach the jumper wire from run to capacitor and second jumper wire from start to capacitor.
■     Disconnect jumper from motor run terminal.
■    Turn on the line voltage and hold jumper wire by the insulation; then hold jumper to run for four seconds, four times at four-second intervals.
■     If motor does not reverse, repeat step six using 240 volts ac instead of 120 volts ac motor rated voltage. Use 480 volts ac instead of 240 volts ac for a motor rated at the higher voltage (single-phase).

Check the capacitor for a higher rated voltage. When you have completed steps one through seven using double line voltage, you have hot-shotted the compressor in reverse. Do not hot-shot in re­verse until you have done steps one through seven with rated line voltage for the compressor. You might be able to break the locked rotor with normal line voltage. There is no need to strain the compressor motor unless absolutely necessary. If these steps don’t free the locked rotor, there is nothing else you can do in the field. That covers the important electrical problems that you will find in the field with a compressor. The other malfunction of the compressor is mechanical failure.


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