Capacitors are used on refrigerant motors. Which statement describes their function?

• A. Regulate the motor speed
• B. Store electrical charges during starting and running the motor
• C. Cool the motor windings
• D. Increase refrigerant flow

Answer: (B)

Capacitors in refrigerant motors provide the phase-shifted current that makes a single-phase compressor start and run efficiently. The capacitor supplies a larger current to the start winding to create a rotating magnetic field, giving the motor the initial torque it needs to start. Once the motor is up to speed, a switch (in the case of a start capacitor) removes it from the circuit, while a run capacitor may stay in place to improve running efficiency and torque by maintaining the proper phase relationship between windings. In short, capacitors store electrical energy to help start and continue running the motor, which is why describing their function as storing charges during starting and running is the best fit. They do not regulate speed, cool windings, or increase refrigerant flow.