CFESA Refrigeration Certification Practice Test 2026 - Free Commercial Food Equipment Service Association Practice Questions and Study Guide

In a potential relay, the coil is typically wired across the common and start terminals. This configuration is crucial for the operation of the relay because it allows the relay to sense the voltage generated by the motor's starting winding when power is applied.

When the compressor motor starts, the difference in potential between the common and start windings creates a voltage across the relay coil. This voltage is what activates the relay, allowing it to connect the run winding to the power supply after the motor reaches a certain speed. Once the motor is running efficiently, the relay opens the circuit to the start winding, which is essential for protecting the motor from overheating due to prolonged engagement of the start winding.

Understanding this wiring configuration is vital for technicians working with refrigeration systems and ensures that they can diagnose and troubleshoot issues related to motor starting systems.