The difference between fast melt and slow melt

Under the same overcurrent load condition, the action speed of the slow-blow fuse is slower than that of the fast-blow fuse. But this is not because its reaction speed is slow, but it requires more energy to fuse, It can also be said that it not only has a response to overcurrent, It also has the ability to discriminate the type of overcurrent or the magnitude of energy, and the delay time during the action process can be regarded as the time for the slow-blow fuse to judge the overcurrent.

In general, overcurrent can be divided into two categories: surges and faults. The surge overcurrent is mostly caused by the charge and discharge of the circuit switch or the influence of the surrounding circuit. The pulse peak value is large and the duration is short, and the energy released is often not large. Slow-blow fuses can withstand such an overcurrent impact without causing a blown action. The fault overcurrent is continuous. Even if the peak value is not necessarily very high, its energy will greatly exceed the surge overcurrent. As usual, the slow-blow fuse will respond quickly and blow, so from this point of view, the slow-blow fuse The slightly slower action speed not only does not affect its protection function, but enhances its protection function, avoiding the chance ofwrongoperation, and can be used in a wider range of occasions to protect various circuits. On the contrary, the fast-acting fuse can be blown due to the smaller energy. Although the action speed is fast, the reason and occasion are somewhat limited.