Maintenance Technician Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

A bimetallic strip is commonly used in thermal overload relays within electrical motors to prevent overload conditions. When a motor operates, if the current exceeds a certain level, this results in excess heat. The bimetallic strip consists of two different metals bonded together that expand at different rates when heated. As the temperature increases due to excessive current, the strip bends, eventually activating a switch that cuts off the power to the motor. This mechanism effectively protects the motor from damage that could be caused by an overload situation, preventing potential failure or fire hazards associated with overheating.

The other options involve different phenomena: corona refers to electrical discharge, corrosion pertains to the deterioration of materials, and eddy losses are related to energy waste in magnetic materials. None of these involve the direct thermal protection offered by a bimetallic strip in motor applications.