air conditioner fuse replacement_mini cooper fuse box factory

14 2024-09

　　The selection of self recovery fuses should pay attention to the following parameters

　　1. Rated zero power resistor: PPTC thermistors should be packaged in stages according to zero power resistors, and the resistance range should be indicated on the outer packaging. After the withstand voltage and current capacity tests, the range of resistance change rate in each group of samples before themselves, δ | Ri after - Ri before/Ri before - (Rj after - Rj before)/Rj before |, is ≤ 100%.

　　2. PTC effect: PTC effect refers to the fact that the resistance of certain materials increases with temperature. In self-healing fuses, PTC effect can improve the protection capability of the circuit.

　　3. Nonlinear PTC effect: Materials undergoing phase transition exhibit a phenomenon where the resistance increases sharply by several to tens of orders of magnitude along a narrow temperature range, known as the nonlinear PTC effect. A considerable number of types of conductive polymers will exhibit this effect, such as polymer PTC thermistors. These conductive polymers are very useful for manufacturing overcurrent protection devices.

　　4. Initial resistance Rmin: The resistance value of the polymer PTC thermistor of the self resetting fuse series tested at an ambient temperature of 25 ° C before installation in the circuit.

　　5. Rmax: The maximum resistance value measured one hour after the self resetting fuse series polymer PTC thermistor is installed or reflow soldered into the circuit board at room temperature.

　　6. Minimum resistance (Rmin)/maximum resistance (Rmax): At a specified ambient temperature, such as 25 ° C, the resistance value of a specific model of self resetting fuse series polymer thermistor before installation in the circuit will be within a specified range, that is, between the minimum value (Rmin) and the maximum value (Rmax). This value is listed in the resistance column of the specification sheet.