Definition
A protective device in an electrical circuit that automatically opens the circuit when the temperature of a component or the device itself rises above a preset safe limit. Once the temperature falls back to a safe level, some thermal cutouts reset automatically, while others must be reset manually.
Plain English
A heat-sensitive switch that shuts off power when something gets too hot, protecting the equipment from damage or fire.
Context Anchor
Seen in aircraft electrical systems, component manuals, and troubleshooting for equipment that can overheat, such as motors, lights, heaters, or other powered devices.
Derivation
Thermal comes from the Greek thermē, meaning heat. Cutout describes a device that cuts (interrupts) a circuit. Together: a device that cuts the circuit when it gets hot.
Why Pilots Care
It prevents electrical fires and protects wiring and motors from burnout during overloads.
Intuition Check
A thermal cutout is not a part that has been physically cut out. It is a heat-triggered switch that shuts off electrical power when the temperature gets too high.
Example Sentence 1
When the generator overheated, the thermal cutout opened the circuit and removed the generator from the bus.
Example Sentence 2
Technicians replaced the thermal cutout after it tripped repeatedly in the generator circuit.