What happens if the holding contact in a motor circuit fails?

A holding contact in a motor circuit is crucial for maintaining the operation of the motor once it has been started. When the start button is pressed, power is supplied to the motor, and the holding contact keeps the circuit closed, allowing the motor to continue running even after the button is released.

If the holding contact fails, it means that the connection is broken, leading to an interruption in the circuit. As a result, the motor will stop because it no longer has the necessary electrical path to continue operating. Furthermore, the failure of the holding contact means that the motor will not automatically restart when the start button is pressed again. This situation ensures that the motor remains off until someone intervenes, typically by resetting the circuit or addressing the failure of the holding contact.

Other potential outcomes from a holding contact failure, like the motor running continuously or the overload reset tripping, are not associated with the function of holding contacts. The design of motor circuits aims to ensure safety and control, and a failure in the holding contact directly affects operational continuity by preventing the motor from restarting without corrective action.