How to Troubleshoot a Single Phase Cap Start Motor

If the Motor Won't Start

• 1

  Ensure the motor's power is off. Use the meter to make sure there is no voltage present. Check the motor for any physical damage, such as discoloration, burned wires or a bent drive shaft.

• 2

  Attach the meter to the line leads and turn the power back on to make sure the motor's power is working; turn the power back off when you are done.

• 3

  Check the capacitor. First, discharge it by touching an insulated screwdriver blade to the terminals. Then use the ohm meter to determine if there is continuity throughout the motor circuits.

If the Motor Starts

• 4

  Ensure the motor is the proper size so it does not overheat when it comes up to speed. Do not exceed the maximum amperage on the nameplate; install a larger motor if necessary.

• 5

  Check the voltage level with the volt meter. If the voltage is not within 10 to 15 percent of the expected level, this could indicate a problem with the external wiring capacity.

• 6

  Check the ambient temperature during primary use of the motor if overheating is a problem. The nameplate should indicate the proper temperature for operation. Make sure any testing takes place at the same temperature as regular use.