What is the purpose of a holding circuit in motor control?

The purpose of a holding circuit in motor control is to maintain power to a relay or contactor after initial engagement. After a momentary switch is pressed to start the motor, the holding circuit ensures that the relay or contactor remains energized even after the switch is released. This is accomplished by creating a parallel path for the current, which allows the contactor to stay closed and the motor to continue running without needing continuous manual input.

This functionality is crucial for automated control systems where continuous operation is required after the start command. It also enhances the ease of use, as operators do not need to keep holding a button to keep the motor running. During typical operation, once the initial engaging action is completed, the hold circuit "holds" the relay or contactor in the closed position until an intentional stop command or an overload event occurs.