Switch Selection Instructions
The selection of the switch is specific to the switch itself. The selection of the switch mainly has the following aspects:
(1) The appearance of the switch. The appearance here refers to the body of the switch and the switch (or symbol card). The high-quality switch panel should use high-grade plastic switch, that is, the material is uniform, the surface is smooth and textured, such as the commonly known PC material (polycarbonate, short for Polycarbonate). This switch material has excellent flame retardancy, insulation and impact resistance, and the material is stable and not easy to change color. The use of such materials to produce switches and sockets can greatly reduce the occurrence of fires and other conditions caused by electrical circuits. It should be pointed out here that at present, most of this material in China depends on imports, because the PC materials produced by a few domestic manufacturers are not as large as required, and most are produced using recycled raw materials, so the switch itself has been lost. The original function. In addition, regarding the switch or symbol card, good switches are all printed with laser resin, which is not easy to fall off and wear;
(2) The internal structure of the switch. On the switch of the switch, there is a silver-white contact, which is used to control the switching current on and off. Good switch contacts are all silver alloys (silver-nickel alloys, silver-chromium alloys, etc., because silver has the best electrical conductivity, and silver alloys have the strongest ability to suppress arcs), no matter what alloy, the purpose is It is to enhance the hardness of silver and increase its melting point to prevent the melting of silver when the current is too large; or to prevent the oxidation caused by the arc during opening and closing. In addition, for the switch itself, it is a current-carrying member (for carrying current), and the material of the switch must be a copper alloy (if it is pure copper or brass, it does not meet the requirements);
(3) The functional style of switch. Mainly involves the following aspects: switch gear, circuit principle, symbol card icon and function, etc. The switch of a general switch is 2-bit or 3-bit, including whether there is a stable bit, and the circuit may also include a diode. The load-carrying current of the switch in the circuit is generally about 10A. In addition, a good switch should have clear requirements or quantitative indicators on the stability and service life of the function, and it should also meet the international ISO standards in the type and function of the symbol;
(4) Switch wiring and installation method. Generally speaking, the way of wiring is an important standard for verifying the safety of electricity. For the connection terminals and the attached connectors, their protection levels and sealing standards should also have corresponding quantitative values. Most switches have two methods of direct terminal connection and plug connector connection, users can choose arbitrarily.
