A. Select the fuse model according to the line requirements and installation conditions
For circuits with small capacity, choose semi-enclosed or non-filled closed; for large short-circuit current, choose filled-enclosed; choose fast fuse for semiconductor component protection.
B. Select the rated voltage of the fuse according to the line voltage
C. Select the rated current of the fuse according to the load characteristics
D. The selection of melts at all levels needs to cooperate with each other. The latter stage is smaller than the previous stage, the current on the main gate and each branch circuit is different, and the fuse selection for the high-voltage wall bushing is different.
If the circuit is short-circuited, the 15 A and 25A fuses will be blown at the same time, and the protection characteristics will lose selectivity.
If the selection is too small, one-phase fuse is likely to be blown in the high-voltage load switch, causing the motor to burn out due to single-phase operation; according to statistics, 60% of the motors that burn out are caused by improper fuse configuration.
High-voltage fuse is a protection device for power and lighting circuits. When a short circuit or fault occurs, high-voltage insulators can quickly cut off the power supply to protect the safety of the circuit and electrical facilities. So we should choose and use high-voltage fuse correctly.