What is the device that removes the start capacitor from the electric circuit when the compressor is up to speed?

What is the device that removes the start capacitor from the electric circuit when the compressor is up to speed?

• A. Disconnect switch
• B. Defrost relay
• C. Potential relay
• D. High pressure safety switch

Answer: (C)

When a single‑phase compressor starts, the start winding with the capacitor provides the needed initial torque. Once the motor reaches speed, that extra torque isn’t needed and keeping the start circuit energized would waste energy and cause heat. The device that automatically removes the start capacitor from the circuit as the compressor comes up to speed is a potential relay. It senses the motor’s condition (voltage/current) and, when the speed is sufficient, releases its contact to disconnect the start winding and capacitor from the circuit. The other devices listed don’t perform this automatic removal: a disconnect switch is a manual power cut; a defrost relay handles defrost cycles; a high‑pressure safety switch protects against overpressure.

When a single‑phase compressor starts, the start winding with the capacitor provides the needed initial torque. Once the motor reaches speed, that extra torque isn’t needed and keeping the start circuit energized would waste energy and cause heat. The device that automatically removes the start capacitor from the circuit as the compressor comes up to speed is a potential relay. It senses the motor’s condition (voltage/current) and, when the speed is sufficient, releases its contact to disconnect the start winding and capacitor from the circuit. The other devices listed don’t perform this automatic removal: a disconnect switch is a manual power cut; a defrost relay handles defrost cycles; a high‑pressure safety switch protects against overpressure.