What circuit(s) is(are) energized after the compressor motor reaches operating speed?

When a compressor motor reaches its operating speed, the circuit that remains energized consists of the running windings. This is due to the design of most single-phase or three-phase motors, where the starting windings are used only to initiate motor rotation. Once the motor has accelerated to a designated speed, a relay or switch opens the circuit to the starting windings, ensuring that only the running windings are powered for efficient operation.

In contrast, if the starting windings were still energized, it could lead to overheating and damage because they are not designed for continuous operation. Energizing both sets of windings simultaneously could also result in unnecessary energy consumption and reduced efficiency. Therefore, the correct understanding of motor operation clarifies that the running windings are specifically designed to maintain the motor's operation after achieving the necessary speed, while the starting windings are disengaged to protect the motor and ensure optimal performance.