Thermal overload relays are protective appliances used for overload protection of motors or other electrical equipment and electrical lines. In the actual operation of the motor, for example, in the process of dragging the production machinery to work, if the machinery is abnormal or the circuit is abnormal and the motor is overloaded, the motor speed will drop and the current in the winding will increase, which will make the winding temperature of the motor. If the overload current is not large and the overload time is short, and the motor winding does not exceed the allowable temperature rise, this overload is allowed.

