Introduce Several Commonly Used Low-voltage Fuses
The fuse has the advantages of simple structure, low price, convenient use and maintenance, and small size. The following are some commonly used low-voltage fuses.
Porcelain plug-in fuse (RC1A)
The porcelain plug-in fuse is composed of five parts: porcelain cover, porcelain low, moving contact, static contact, and fuse. Both the porcelain cover and the porcelain low are made of electrician porcelain. The power line and the load line can be connected to the static contacts at both ends of the porcelain low, respectively. The RC1A fuse is cheap and easy to replace and is widely used in the circuit breaker protection of lighting and small-capacity motors.
Spiral Fuses (RL)
Spiral fuse is mainly composed of a porcelain cap, fuse tube, porcelain sleeve, upper terminal, lower terminal, and seat.
In the fuse RL1 series spiral fuse, the quartz sand is filled around the fuse to extinguish the arc. There is a small red dot on the upper end of the tube. After it is blown, the red dot automatically falls off, indicating that it has been blown. When in use, insert the red-dotted end of the tube into the porcelain cap. The porcelain cap has threads, screw the nut together with the tube into the porcelain lower seat.
During installation, the connecting wire of the electrical equipment is connected to the upper terminal of the metal threaded shell. The power wire is connected to the lower terminal of the base so that when it is replaced after the nut is screwed, the threaded shell will not be connected. charged.
Unpacked Enclosed Tube Fuses (RM)
Non-filled closed tube fuse, consisting of a fuse tube (ie fiber tube), two sockets, and one or two fuse pieces. The fuse is a zinc sheet with one or several narrow sections, which is installed in the tube and contacts the socket through the cap of the tube to form a current path. Its shape and structure are shown in the figure below: when the melting piece is working normally, the wide part of the melt can conduct the heat generated by the narrow part, so it can withstand a large long-term working currently. Under the short-circuit current, the narrow neck of the melt is blown first, which is to artificially introduce a weak link in the melt, and hope that this weak link will give full play to its function during short-circuit to improve its current breaking capacity.
Filled Enclosed Tubular Fuses (RTO)
The filled closed tube fuse is mainly composed of a tube body, indicator, quartz sand filler, and melt.
Its tube body is made of talc ceramics, and the outer surface of the tube body is made into a wave shape, which not only increases the surface heat dissipation area but also is more beautiful. There are four screw holes at each end of the inner circle of the tube body so that the cover plate can be installed with screws. on the tube body. The upper cover is equipped with a clear red indicator to indicate the working condition of the fuse. When it is blown, the indicator is bounced up. The melt is punched into sieve holes with thin copper sheets and surrounded by a cage. Pure tin is welded in the middle, and both ends of the melt are spot welded on the metal plate to ensure good contact between the melt and the conductive insert. The tube is filled with specially treated quartz sand to cool and extinguish the arc.
Since silicon semiconductor components are increasingly widely used in industrial power conversion and power driving devices. But the PN junction has the low thermal capacity and poor overload capacity of silicon semiconductor components. It can only withstand overload current in a very short time, otherwise, the semiconductor components will be quickly burned out. To this end, a fast-acting fuse that can act quickly in the event of an overload must be used.
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