How are the thermal overload contacts on a line starter usually reset?

The thermal overload contacts on a line starter are typically reset manually. When the overload condition occurs, the thermal overload relay opens its contacts to protect the motor from overheating and potential damage. This action interrupts the power supply to the motor, ensuring that the motor is not further damaged by continued operation under excessive load.

To restore power and reactivate the motor after it has been tripped, an operator must manually reset the thermal overload relay. This manual reset feature is intentionally designed to ensure that an operator assesses the underlying cause of the overload before restarting the motor, thereby promoting safety and preventing repeated tripping due to ongoing issues.

In contrast, automated, remote, or electronic resets are not standard for traditional thermal overload contacts, which prioritize a manual reset to ensure human intervention and understanding of the equipment's status.