The Thermal Overload Protector on a motor monitors both motor temperature and current. When either exceeds the motor's limit, the Protector will shut the motor off until it cools. Overheating or high current are generally caused by other factors that overload the motor, like substituting the wrong motor or lack of proper ventilation around the motor. Occassionally, however, the Thermal Overload Protector goes bad and must be replaced. This guide shows you where the Thermal Overload Protector is located on a typical AO Smith motor, and how to replace it. This guide is specific to an AO Smith motor but many of the steps are applicable to other makes.
Click here to view A.O. Smith motor parts.