fuses used for protection in low-voltage power supply lines.

Introduction of low-voltage fuse:

1. Features:

1. The fuse has low melting point, large resistance and small cross section.

2. In the process of melting and cutting off the circuit, an arc will be generated. In order to extinguish the arc safely and effectively, the melt is generally installed in the fuse housing, and measures are taken to extinguish the arc quickly.

3. Fuses are widely used in low-voltage systems because of their simple structure, convenient use and low price.

4. The rated current of the melt is not equal to the rated current of the fuse. The rated current of the melt is selected according to the load current of the protected equipment, and the rated current of the fuse should be greater than the rated current of the melt, which should be determined in coordination with the main electrical appliance.

2. Type:

1. Porcelain plug-in fuse (RC1A): Porcelain plug-in fuse consists of five parts: porcelain cover, porcelain lower, moving contact, static contact and fuse. Both the porcelain cover and the porcelain base use the title of electrical porcelain, and the power line and load line can be connected to the static contacts at both ends of the porcelain base respectively. There is a cavity in the middle of the porcelain base, which forms an arc extinguishing chamber with the protruding part of the cover. RC1A fuse is cheap and easy to replace. It is widely used in lighting and circuit breaker protection of small-capacity motors.

2. Screw fuse (RL): The screw fuse is mainly composed of porcelain cap, fuse tube, porcelain sleeve, upper terminal, lower terminal and seat.

3. In the fuse of RL1 series spiral fuse, quartz sand is filled around the fuse in addition to the fuse to extinguish the arc. There is a little red dot at the upper end of the fuse tube, and the red dot automatically falls off after the fuse is blown, indicating that the fuse has been blown. When in use, insert the red-dot end of the fuse tube into the porcelain cap, and the porcelain cap is threaded. Screw the nut together with the fuse tube into the porcelain base, and the fuse will be connected to the circuit.

4. Packing-free closed tube fuse (RM): A packing-free closed tube fuse consists of a fuse tube (i.e., a fiber tube), two sockets and one or two fused sheets. Fuse fuse is a zinc sheet with one or several narrow sections, which is installed in the fuse tube and contacts the socket through the cap of the fuse tube to form a current path.

5. Filled closed tube fuse (RTO): Filled closed tube fuse is mainly composed of tube, indicator, quartz sand filler and melt. Its tube body is made of talc ceramics, and the outer surface of the tube body is wavy, which not only increases the heat dissipation area of the surface, but also is beautiful. There are four screw holes at both ends of the inner circle of the tube body, so that the cover plate can be installed on the tube body with screws.

6. Fast fuse: Because silicon semiconductor components are increasingly widely used in industrial power conversion and electric traction devices, the thermal capacity of PN junction is low, and the overload capacity of silicon semiconductor components is poor, so they can only bear overload current in a very short time, otherwise the semiconductor components will be burned out quickly. Therefore, it is necessary to adopt a fast fuse that can act quickly when overloaded.