The role of compressor overload protector
Overload protector is called overload and overheat protector or overheat protector. As the name suggests, it is set to prevent the compressor from overheating and overcurrent damage. When the compressor running current is normal, the overload protector is in the on state, and the compressor works normally. When the compressor's working current is too high or the working temperature is too high due to abnormal power supply, abnormal starter, etc., the overload protector will act and cut off the compressor's power supply circuit. The compressor stops working to achieve the purpose of protecting the compressor. Its installation position on the compressor is shown in Figure 1.

Classification
There are mainly two types of overload protectors used in refrigerators: external type and built-in type. The starter and overload protector of some old-fashioned refrigerators are integrated. The compressor overload protector is shown in Figure 8.

3. Composition and working principle of overload protector
The following takes the most commonly used disc compressor thermal protector as an example to introduce the composition and working principle of the overload protector.

Figure 9, it is composed of resistance wire, bimetallic strip and a pair of normally closed contacts. It is connected in series with the compressor power supply circuit, and the open end is closely attached to the compressor casing. When the current is too large, the temperature of the resistance wire rises, and the bimetallic sheet is baked to bend it in the opposite direction, so that the contacts are separated and the power supply circuit of the compressor is cut off. In the same way, when the temperature of the compressor casing is too high for some reason, the bimetallic strip is heated and deformed, which separates the contacts and cuts off the power supply circuit, which will also achieve the purpose of protecting the compressor.




hint: The compressor power is different, the matched overload protector model is different, and the switch-on and switch-off temperature are also different. The overload protector of the same model or the same specification should be replaced when repairing, so as not to lose the protection function and bring harm to the compressor. The overload protector of refrigerators using R600a fluorine-free refrigerant is explosion-proof. That is, it is built-in closed, and there should be a yellow flame flammable sign on the nameplate.