What is the principle of bimetal disc thermal protector?

What is the principle of bimetal disc thermal protectors?


Bimetal disc thermal protector —— is a common temperature protection device,

which is welded by two metal sheets with different expansion coefficients,

and is usually used in ACl motors, heating appliances, power tools and other fields.

It can be preset to its shape and parameters according to different conditions of use and safety requirements. When the ambient temperature reaches a certain value, the bimetal disc will deform and cut off the power supply.

The working principle is to use the bending deformation caused by different metal expansion rates to achieve break protection.

  • When the temperature rises to the warning value, due to the different expansion rates of the two metal sheets, the deformation of the active layer will be greater than the other, and the whole will bend to one side, thus pushing the contact to open and playing the role of protecting the circuit.

  • After a period of time, the temperature drops to a safe range and the bimetal disc resets. Then, the contact closes and the circuit are re-energized.

  • It should be noted that the selection of thermal protectors should be reasonably matched according to the type of motor, power, use conditions, operating current/voltage, and other factors. Also, follow the instruction manual for proper installation.

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