Fuse selection considerations

1. Fuse selection tips:

The fuse is mainly selected according to the condition of the load and the magnitude of the circuit breaking current.

For example, for the protection of small-capacity lighting lines or adjustable motives, RC1A series plug-in fuses or RM10 series non-filled sealed tube fuses should be used; for circuits with large short-circuit current or flammable gas, Use RL series spiral fuses with high breaking capacity or RT (including NT) series with sealed closed tube fuses; for the protection of silicon rectifier devices and thyristors, fast fuses should be used.

2. Principles to follow when selecting fuses:

1) Determine the type of fuse according to the conditions of use.

2) When selecting the specifications of the fuse, the specifications of the melt should be selected first, and then the specifications of the fuse should be selected according to the melt.

3) The protection characteristics of the fuse should be well matched with the overload characteristics of the protected object.

4) In the power distribution system, the fuses of each stage should be matched with each other. Generally, the rated current of the upper stage melt is 2 to 3 times larger than the rated current of the next stage melt.

5) For the protection of the fuse of the motor, attention should be paid to the influence of the motor starting current. The fuse is generally only used as the short-circuit protection of the motor, and the overload protection should use a thermal relay.

6) The rated current of the fuse shall not be less than the rated current of the melt; the rated breaking capacity shall be greater than the maximum short-circuit current that may occur in the circuit.