Explosion-proof lighting cavity electrical structure mainly includes what content
1. Electrical components The electrical components should meet the requirements of relevant national standards, be able to withstand the operating temperature of the lamp cavity for a long period of time, provide electrical parameters that are compatible with the light source, and be compatible with the requirements of various explosion-proof lamps.
2. The design of wiring chamber wiring chamber structure dimensions must meet the specific explosion-proof performance requirements, and it should be easy to connect, leaving space for the bending radius of the wire, to ensure that the correct clearance after the clearance and creepage distance meet the relevant standards, wiring chamber wall and The inner wall of the metal shell that may generate sparks during normal work must be painted with arc paint.
3. Connections and terminals
1 The connecting piece, insulation bushing and terminal shall have sufficient mechanical strength to prevent damage during installation. The wiring should be solid and reliable, prevent loosening, and can not be loosened due to vibration, heat, thermal expansion and contraction of the conductor and insulation.
2 The power connector should be designed so that if multiple stranded conductors are connected, if the cable head comes out of the terminal, it will not touch the surrounding metal parts.
3 Terminals should take measures to prevent loosening to prevent the wire at the root of the terminal from being twisted. It is not allowed to press the connecting wire directly with the screw head, which will easily damage the wire head.
Explosion-proof electrical appliances which types
The types of explosion-proof electrical appliances are divided into two categories according to the specific use environment: one is for underground coal mine electrical equipment and the other is for factory electrical equipment. According to the characteristics of sparks, arcs, and dangerous temperatures generated by electrical equipment and measures taken to prevent them from igniting explosive mixtures, the following eight forms are available:
(1) Flameproof type (mark d); is an electrical device with a flameproof enclosure that can withstand the explosion pressure of the internal explosive gas mixture to prevent the internal explosion from propagating to the explosive mixture around the enclosure. Suitable for any place of explosion hazardous locations.
(2) Increased safety (mark e). Under normal operating conditions no arcs, sparks, or high temperatures sufficient to ignite the explosive mixture will occur. Various measures are taken structurally to increase safety to avoid arcs, sparks and high temperatures under normal and recognized overload conditions.
(3) Intrinsically safe (marks ia, ib): IEC76-3 spark test device is used. EDM and thermal effects resulting from normal operation or specified fault conditions do not ignite the specified explosive mixture. This kind of electrical equipment is classified into ia and ib according to the place of use and the degree of safety. The ia rating device does not ignite the explosive gas mixture during normal operation, one failure, and two failures. An ib rating device cannot ignite an explosive gas mixture during normal operation and failure.
(4) Positive pressure type (mark p): It has a positive pressure enclosure that can maintain the internal protective gas, that is, the pressure of fresh air or inert gas is higher than the surrounding explosive atmosphere, preventing the external mixture from entering the enclosure.
(5) Oil-filled type (mark U): It is an oil or a part of the electrical equipment, so that the equipment cannot ignite the explosive mixture above the oil surface or outside the housing, such as a high-pressure oil switch.
(6) Sand-filled type (mark q): The sand material is filled in the outer shell so that under the conditions of use, arcing, flame propagation, shell wall, or sand material surface overheating of the shell cannot ignite the surrounding explosive mixture.
(7) Non-spark type (mark n): Under normal operating conditions, the surrounding explosion mixture will not ignite, and generally no ignition failure will occur.
(8) Special type (marker s): Refers to electrical equipment that does not belong to any of the above categories, but uses other special explosion-proof measures. Such as the filling of sand and sand type equipment is such.
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