In a good single-phase compressor motor, which winding terminals typically have the highest resistance?

In a single-phase compressor motor, the winding terminals that typically have the highest resistance are between the run and start windings. This is due to the fact that the start winding is designed to help the motor start and is usually wound with a finer wire over a smaller number of turns compared to the run winding. Consequently, the start winding tends to have more resistance due to its design and the materials used.

When the motor starts, the start winding is energized for a brief period to provide the necessary phase shift to create the rotating magnetic field required to initiate rotation. Once the motor is up to speed, the start winding is typically disengaged from the circuit, leaving primarily the run winding in operation, which will have lower resistance overall.

Understanding the resistance characteristics of these windings is critical as it impacts motor performance and efficiency. In practice, a technician may use the resistance readings to troubleshoot compressor motor issues or ensure proper motor function during maintenance checks.