What Is Motor Temperature Protection?

Most motors use an electronic sensor to measure temperature.

Because they require an optimal temperature range for operation, most motors have some form of temperature protection. Temperatures beyond or below that range can cause the motor to operate poorly or damage the components.

Protection

If ambient or internal temperatures exceed the motor's operating specifications, a motor temperature protection instrument ensures that the motor isn't damaged by signaling an operator who can take action to cool it, or triggering a fail-safe that will slow or shut it down.

Components

A motor temperature protection device will most often use a thermostat to detect temperature change. This may include the use of bimetal sensors, wax pellets, and electronic devices.

Bimetals

Bimetals are composed of two metals joined together in thin layers, which expand at different rates and different directions depending on the temperature. Its purported inventor was John Harrison, a clock maker during the 18th century. Bimetals are used in clocks, thermostats, thermometers, heat engines, and miniature circuit breakers.

References

• US Motors: Methods of Winding Temperature Protection
• Spectrum Sensors: Motor Protection Sensor
• Serving History: Bi-Metallic Strip History