At what part of the AC cycle is the motor current highest?

The motor current is highest at startup because, during this phase, the motor experiences the maximum load. When the AC system is turned on, the compressor and fans need to overcome inertia to begin operation, requiring additional energy. This surge in current is necessary to start the compressor's motor, which draws a significant amount of electricity to initiate movement.

Once the system is running and the compressor has reached operational speed, current levels drop to a more stable and lower level, consistent with what is needed for continuous operation. During cooling operation, the current is maintained to power the system efficiently, but it will not reach the elevated levels seen during startup. In idle mode, the system is not operational, resulting in minimal to no current draw.