The working principle of TP1 is: the thermal protector is connected to the load circuit in series, the load current enters the protector through one end of the wire lead, passes through the bimetallic sheet component of the thermal protector (see the attached figure: the structure diagram of thermal protector), and then flows out from another lead of the thermal protector.

The shell of TP1 is stainless steel (insulated by insulating sleeve), whose surface is installed on the protected element, the temperature rise of the protected element can be well transmitted to the inner of the thermal protector through the shell, so that the bimetallic sheet of the thermal protector acts. The temperature response time is generally between 2.5 min and 3.5 min.

Among them, bimetallic sheet is a kind of shape memory metal, temperature rise will change its shape, when temperature recovery, it will return to its original state. We stabilize it at a certain temperature through technological means, and it becomes a switch assembly for that temperature. Because the bimetallic sheet itself has resistance, the current through will cause its own heating, if the current is too large, the heat caused by the product can make the thermal protector action. Therefore, the temperature compensation caused by its own heating should be considered during use.

Specifically on the TP1 series, the bimetallic sheet of 2.5A TP1 uses a high resistance sheet with resistivity of 110u Ω..cm, which is more sensitive to current; The bimetallic sheet of 10A uses a low resistance sheet with a resistivity of 8.6 u Ω. cm, which is relatively less sensitive to current. For the 10A parts, the most important thing is to feel the outside temperature. Therefore, the temperature rise rate of the protected element and the heat transfer rate of the thermal protector are the two most important parameters that users must consider. It determines which temperature of the thermal protector is appropriate to users.