The structure design is simple, consisting of strip-shaped high-sensitivity bimetallic elements, moving contacts, static contacts, screws, cover plates, etc. The bimetal element is placed on the bottom shell, the moving contact and the static contact are closed, and the circuit is conducted. When the electrical appliance heats up for some reason, and the temperature rises to the rated operating temperature of the product, the bimetallic element is heated to produce internal stress and act quickly, disconnecting the contact, cutting off the power supply, and stopping the electrical appliance, thus playing a protective role against overheating. When the temperature of the protected electrical appliance drops to the product's rated reset temperature value, the bimetal element returns to its original state. The moving and static contacts are closed, and the electrical appliance resumes operation. The protection function of the product can be divided into two types: normally open type and normally closed type, that is, when the temperature reaches the design value, the circuit is turned on and the circuit is turned off.
Due to the use of a metal shell, the protector has stronger mechanical strength and can be covered with an insulating sheath to insulate the metal parts of the motor.