The fusing of the fuse is caused by the melting of the melt by the heat energy released by the overcurrent, and the energy that can fuse the fuse is the melting heat value I²t of the fuse. Theoretically, as long as the energy required for fuse melting is greater than the energy released by the instantaneous pulse current, the fuse will not break, which also means that the fuse can resist the impact of this pulse. Generally, the slow-break fuse will have this characteristic.
Has the fuse that withstands a transient pulse changed? It depends on the damage of the pulse. If the pulse energy is far less than the melting heat value of the fuse, and the impact on the fuse is very small, then the fuse can accept many shocks without breaking. On the contrary, if the pulse energy is close to the melting heat value of the fuse, and the damage to the fuse is very large, then it cannot withstand the second shock, That is to say, the fuse will be damaged to a certain extent after being impacted by each pulse, that is, its impulse resistance will be weakened or I²T decreases, and the degree of weakening or reduction is proportional to the energy of the pulse.
In order to make the fuse withstand the impact of multiple instantaneous pulses, There must have enough margin between I²T and pulse energy. Due to different service life and switching frequency, different electrical products need to bear different pulse times, so the fuse supplier should provide corresponding reference data, that is, corresponding to different pulse times, I²T of fuse should be selected Different multiples of pulse energy.
