company news about Why do we need to use DC fuses in rail transit applications?

        In the power rail transit system, many places need fuse protection to cut off the direct fault current. Typical examples include main circuit, regenerative DC converter, AC converter, auxiliary circuit air conditioning, lighting and other circuits), crowbar system (used for braking DC motor).

        In many underground rail transit systems, the propulsion circuit of trains adopts the DC power supply mode of three-rail current collector. The basic components of current collector are collector shoe and DC fuse. In other rail transit systems, the propulsion circuit of the train often adopts the DC power supply mode of the pantograph. There will be a fuse box near the pantograph, with a DC fuse inside.

        Generally, the task of this fuse is to protect people and equipment to avoid damage caused by the insulation of power cable connecting the current collector (or pantograph) and the propulsion circuit and damage caused by motor failure. If there is no fuse protection, it will cause serious fire.

        The safety requirements of rail transit determine that the tubular fuse must be used and the protective action must be carried out in a completely closed manner. The time constant and overcurrent range of DC fuse applied in rail transit are large. The DC fuse with good design provides sufficient length for arcing and can withstand the huge pressure generated by arcing. While withstanding the impact of arcing, the DC fuse also maintains a relatively compact overall dimension of the fuse.