Rated voltage: The rated voltage of the fuse should be greater than the nominal voltage of the applicable electrical system to accommodate possible overvoltage conditions. In the event of overvoltage, the fuse may explode and other dangerous conditions.
Rated current and continuous working current: The rated current is used to indicate the specification of the fuse. The continuous working current refers to the maximum current continuously flowing through the circuit at the highest ambient temperature. The continuous working current should be less than the rated current.
Connection resistance: A large connection resistance will cause the temperature at the contact point of the fuse to rise, and the operating current will decrease accordingly. In actual engineering, the fuse, sheath and connector specified by the OEM should be tested to achieve thermal equilibrium. Should not exceed the prescribed range.
Ambient temperature: The characteristic curve of the fuse is closely related to the ambient temperature. Exceeding the temperature range of its use, it will cause the internal resistance of the fuse to rise, further increasing its temperature, which will cause the fuse to derate. When selecting a fuse, the ambient temperature should be considered and the corresponding derating factor should be used.
Time-current characteristics: In the final analysis, the fuse is current protection. The circuit is cut off before the wire is fired. Therefore, the fuse should be selected before the maximum operating temperature Tmax of the wire is exceeded, so as to ensure the safety of the system.
Selectivity: The fuse should be layered. During the design process, the underlying fuse should be blown first, and the high-level fuse should be blown or not blown, so as to ensure that the single fault does not affect the normal operation of the electrical system of the higher-level system. .
Surge resistance of the fuse: The circuit of the whole vehicle system is complex and changeable. In the process of selecting the fuse, not only the continuous working current and rated current should be considered, but also the surge characteristics of the electrical appliance should be considered to ensure that it can withstand the surge. Without melting.