When you see the term“Thermal protector” When used to describe electric motors, it refers to a device within the motor or motor compressor that is used to prevent dangerous overheating that could cause motor failure, called a motor thermal protector.

Use motor thermal protector

This overheating usually occurs when the motor is overloaded, the bearings are seized, something is locking the motor shaft and preventing it from turning, or the motor will not start properly. Faulty starting can be caused by a faulty motor starter winding.

MotorThermal protectorConsists of one or more heat sensitive components built into the motor or motor compressor and an external control device. When too much heat is generated in the motor circuit, the thermal protection device shuts down the motor. This safety feature stops when the temperature rises and then burns the motor.

Once the motor has cooled to a safe operating temperature, the motorThermal protectorUsually resets automatically. There is usually a visible red button on the wiring side of the motor, which is usually, though not always, located opposite the motor shaft. On motors mounted in this way, this button must be pressed to reset and restart the motor. On other motors that do not have a reset button, the reset occurs automatically when the motor cools.

It's inconvenient to shut down a motor because a thermal limit tripped, but it's certainly better than overheating and having to replace the motor. In addition, a shutdown can alert you that there's a problem with the motor or connected equipment, or with the load on the motor. When a motor fails to start or overheats while in operation, it may be a sign that the motor has reached the end of its useful life and must be replaced. But often the fault is not with the motor at all. For example, the load attached to the motor may have an obstruction that causes excessive load and causes heat to build up in the motor.

When purchasing equipment with a motor, the motorThermal protectorGenerally a very good feature. By preventing the motor from overheating, it can greatly extend the life of the motor.