What do thermal overloads specifically protect within a starter?

Thermal overloads are devices designed to protect electric motors from being damaged due to overheating caused by excessive current. When a motor operates under heavier loads than it is rated for, it draws a higher current, which increases the temperature. If this condition continues, it can lead to insulation failure or irreversible damage to the motor's windings.

The thermal overload relay senses the temperature increase caused by the excess current and will interrupt the circuit to the motor, effectively shutting it off before permanent damage can occur. This function is vital in ensuring the longevity and reliability of motors within various industrial applications, making thermal overload protection particularly crucial in starter circuits where motors are initiated and controlled.

Transformers, circuit breakers, and capacitors serve different purposes in electrical systems and their protection mechanisms differ from that of motors, further emphasizing the targeted role of thermal overloads in preventing motor damage.