Troubleshooting PSC Motors

As an HVAC technician, understanding and troubleshooting PSC (Permanent Split Capacitor) motors is crucial for maintaining and repairing air conditioning and refrigeration systems. PSC motors are commonly found in condenser fan motors, evaporator fan motors, and residential compressors, making them an essential component to comprehend.

Identifying PSC Motors

Identifying a PSC motor in the field is relatively simple. A run capacitor wired in configuration with the motor is a clear indication of a PSC motor. Additionally, many residential PSC motors are multi-speed, adding another layer of complexity to their identification.

Testing PSC Motors

When testing a PSC motor, it’s important to understand the wiring and the resistance between the terminals. Using an ohmmeter, the highest resistance will always be between the common and start terminals, followed by the start winding, and then the run winding. Finding the common terminal between the run and start windings is crucial for accurate testing.

Troubleshooting Common Issues

When troubleshooting PSC motors, it’s essential to consider common issues such as locked rotor conditions, shorted, open, or grounded windings. If the compressor motor trips the overload, it indicates a locked rotor condition. On the other hand, if the circuit breaker is tripped, there may be a grounded or shorted compressor winding.

Importance of Run Capacitors

Run capacitors play a vital role in PSC motors by increasing running efficiency. By understanding the impact of capacitance and induction, technicians can grasp the significance of run capacitors in optimizing motor performance.


In conclusion, PSC motors are a fundamental component in air conditioning and refrigeration systems. By mastering the identification, testing, and troubleshooting of PSC motors, HVAC technicians can ensure the efficient operation of these critical components. Stay tuned for more useful tips and techniques to enhance your HVAC knowledge and skills.

For more in-depth knowledge on PSC motors and other HVAC topics, consider exploring resources such as “The Refrigerant Charging and Service Procedures for Air Conditioning” available at and

Remember, a thorough understanding of PSC motors is essential for any HVAC technician, and mastering the troubleshooting process will lead to more efficient and effective maintenance and repair practices.

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