thermostat temperature protector.Detailed explanation of the working principle of temperature controlled fuses_mini cooper fuse box factory

21 2024-09

　　Detailed explanation of the working principle of temperature controlled fuses

　　The characteristic of a temperature controlled fuse is that it will automatically disconnect the circuit when the current is too high or the ambient temperature is too high, in order to protect the components in the circuit from damage. Its working principle is based on the thermal effect. When the current or temperature exceeds the set value, the thermal sensitive material inside the fuse will undergo corresponding changes, causing the fuse to disconnect the circuit. Temperature controlled fuses are widely used in household appliances, automobiles, electronic devices, and other fields.

　　When the ambient temperature reaches a certain value, this thermosensitive material will rapidly expand and damage the internal circuit, achieving an open circuit.

　　The structure of a temperature controlled fuse mainly consists of a housing, a thermistor, contacts, terminals, and other parts.

　　The shell is a sealed component that contains thermal sensitive elements and contacts, and has wire terminals connected to external circuits; Thermistors are usually made of substances such as wax and oil, which rapidly expand at a certain temperature; The function of the contact is to conduct the circuit under normal conditions and be disconnected after the expansion of the thermistor.

　　The working principle of temperature controlled fuses is to utilize the expansion effect of thermal sensitive components. When the ambient temperature is lower than the set value, the volume of the thermistor remains unchanged, the contacts close, and the circuit conducts; When the temperature rises to the set value, the volume of the thermistor rapidly expands, pushing the contacts to break, thereby cutting off the circuit and providing protection. After the temperature drops, the thermistor will shrink back to its original volume, the contacts will close again, and the circuit will return to normal.

　　The parameters of temperature controlled fuses mainly include rated current, rapid melting limit temperature, defined temperature, etc. When selecting, it is necessary to match according to the actual circuit. The rapid melting limit temperature should be slightly higher than the normal operating temperature, while the defined temperature should be much higher than the rapid melting limit temperature in order to accurately provide protection. At the same time, the influence of environmental temperature should also be considered, and appropriate compensation should be made to the fuse parameters if necessary.