A protective device in motors that may reset after cooling

A protective device in motors that may reset after cooling

• A. Thermal Protector
• B. Thermal Cutoff
• C. Circuit Breaker
• D. GFCI

Answer: (A)

The protective device described is a thermal protector. It sits in the motor circuit and uses a bi-metal element that trips when the winding overheats, opening the circuit. Once the motor cools, the element resets automatically, allowing operation to start again. This automatic reset after cooling is the key feature that distinguishes it from other options. A thermal cutoff is a one-time fuse that cannot reset, a circuit breaker is a broader protective device not inherent to the motor winding in the same way, and a GFCI protects against ground faults rather than temperature-related overheating.

The protective device described is a thermal protector. It sits in the motor circuit and uses a bi-metal element that trips when the winding overheats, opening the circuit. Once the motor cools, the element resets automatically, allowing operation to start again. This automatic reset after cooling is the key feature that distinguishes it from other options. A thermal cutoff is a one-time fuse that cannot reset, a circuit breaker is a broader protective device not inherent to the motor winding in the same way, and a GFCI protects against ground faults rather than temperature-related overheating.