Square body fuses, DC

Square body fuses specially tested for DC applications.

Compared to AC circuits, the absence of natural voltage zero in a DC circuit makes it more difficult for a fuse to interrupt the current at fault. It is especially notable in circuits with high time constant.

In general, fuses that are designed and tested for DC shall be used. Some applications are less complex, have a low time constant, in these cases, an AC fuse usually provides sufficient protection. Please note, published data for AC fuses are not valid in DC circuits.

One growing application is then several inverters and rectifiers are connected to a common DC bus. The DC voltage is normally quite high, up to 1000-1200 VDC. High short circuit current levels as well as selectivity between various parts cab be a challenge. Most inverter manufacturer have published fuse selection recommendations. If recommendations are not available, we can assist with recommendations but it requires detailed system design information.

For battery system protection, more manufacturers have started to recommend to use high speed fuses, operating class gR.

Traction systems and generator magnetizing systems, in combination with high currents, a high time constant and exposed environment challenges the fuses. Eaton Bussmann Series offers a wide range for fuses especially designed for traction applications.

Product specialist
Börje Jansson