DC fuse refers to an electrical appliance that fuses the melt with the heat generated by itself and disconnects the circuit when the current exceeds the specified value. The melt melts to disconnect the circuit. A current protector made of this principle. DC fuses are widely used in high and low voltage power distribution systems and control systems and electrical equipment as short circuit and overcurrent protection. It is one of the most commonly used protection devices.

DC fuse is an overcurrent protector. The DC fuse is mainly composed of melt, fuse tube and external filler. When using, connect the DC fuse in series with the protected circuit. When the current of the protected circuit exceeds the specified value value, and after a certain period of time, the heat generated by the melt itself fuses the melt, and the DC fuse disconnects the circuit, thus playing a protective role.

An electrical appliance that uses a metal conductor as a melt to break the circuit is connected in series in the circuit. When an overload or short-circuit current passes through the melt, the melt itself will heat up and fuse, which will play a role in the power system, various electrical equipment and household appliances. It has a certain protective effect and has inverse time delay characteristics. When the overload current is small, the fusing time is long, and when the overload current is large, the fusing time is short.

Therefore, within a certain overload current range until the current returns to normal, the DC fuse will not be blown and can continue to be used. The DC fuse is mainly composed of three parts: the melt, the shell and the support. The melt is the key element to control the fusing characteristics. .

After the melt of the fuse is blown, the cause should be identified first, the fault should be eliminated, and the DC fuse should be blown under the overload current, and the DC fuse should be blown under the breaking limit current. Generally, there is little noise when blown under the overload current. The melt is only blown in one or two places, and there is no adhesion and scorching of a large amount of melt evaporation on the tube wall, while the breaking limit current is the opposite of the above.

When replacing the melt, the melt of the original specification must be selected, and the melt of other specifications must not be replaced, nor can one larger melt be replaced by multiple melts, and it is not allowed to replace it with thin copper wire or iron wire, so as to avoid the occurrence of Major accident.

When replacing the melt (or melting tube), be sure to cut off the power first, turn off the switch, and do not operate with electricity to avoid electric shock, especially do not replace the melt with electricity when the load is disconnected to avoid arc burns.

Insulating gloves and other protective tools should be used for the insertion and removal of DC fuses, and direct manipulation or use of inappropriate tools is not allowed to avoid danger. Find out the specifications of the fuse, and clean the dirt on the inner wall of the tube before installing a new fuse, and tighten the end caps at both ends.

When replacing the fuse of the porcelain plug-in fuse, the fuse should be bent clockwise along the screw and tightened under the washer. Before replacing the fuse, the dirt on the contact surface should be removed first, and then the fuse should be installed. Make mechanical damage to the melt, so as to avoid malfunction due to the reduction of the melt cross-section.

If two phases are broken during operation, three phases should be replaced at the same time when replacing the melt, because the melt of the phase fuse that is not blown has actually been damaged. If it is not replaced in time, the phase will be broken soon.

When replacing the melt, do not cause the melt to be mechanically damaged or strained. The melt is generally soft and easy to break, and is prone to fracture or reduced cross-section, which will reduce the rated current value and affect the operation of the equipment.