This article sorts out the basic knowledge about building strong and weak electricity, and introduces three-phase AC electricity, wire types, lighting installation methods, wire laying symbols, circuit graphic symbols, power distribution equipment graphic symbols, lamps and sockets and other graphic symbols, for only Everyone exchange and study! Incident level: Alternating current: Three-phase AC: Three-phase AC is a power system composed of three AC circuits with the same frequency, equal potential amplitude, and 120° phase difference. At present, my country's production and distribution are all three-phase alternating current. Star (Y-shaped) connection of three-phase power supply: The star connection of phase motors is to connect one end of each phase power supply or load to one point, and the other end of them is used as a lead wire, which are three three-phase power cables. Phase line. For the star connection, the midpoint (called the neutral point) can be led out as the neutral line to form a three-phase four-wire system. It can also form a three-phase three-wire system without leading out. Of course, whether there is a neutral wire or not, you can add a ground wire to become a three-phase five-wire system or a three-phase four-wire system. The advantage is that two different levels of voltage can be simultaneously obtained to supply power to three-phase electrical equipment and single-phase electrical equipment. Wire type: ①BBLX, BBX: Cotton yarn woven rubber insulated aluminum core and copper core wires. ②BLV, BV: plastic insulated aluminum core, copper core wire. ③BLVV, BVV: plastic insulated plastic sheathed aluminum core and copper core wires. ④BLXF, BXF, BLXY, BXY: rubber insulated neoprene sheath, PVC sheath, aluminum core copper core wire. ⑤VLV, VV: PVC insulated, PVC sheathed aluminum core, copper core power cable, also known as all-plastic cable. ⑥YJLV, YJV: Cross-linked PVC insulated, PVC sheathed aluminum core, copper core power cable. ⑦XLV, XV: rubber insulated, PVC sheathed aluminum core, copper core power cable. Wiring type: Click here to download the specification of hydropower atlas for free The installation height of the lighting distribution box should meet the requirements of the construction drawings. If there is no requirement, generally the bottom edge is 1.5m away from the ground, and the installation vertical deviation should not be greater than 3mm. The name of the electrical circuit should be indicated on the distribution box. Wire laying: Lightning protection level: Lightning protection device: Wire representation method: Common wire mark: Equipment representation method: a: equipment number; b: equipment rated capacity; c: Line melt or low-voltage circuit breaker tripping current (A); d: Elevation. Line graphic symbols: Graphical symbols for power distribution equipment: Graphical symbols of lamps: Socket graphic symbol: Switch graphic symbol: Graphical symbols of electric meters: Lamp installation method: Corner cube retroreflectors are designed to reflect any ray or beam entering the prism face, regardless of the orientation of the prism, back onto itself. A mirror will only do that at the normal angle of incidence. As a result, corner cube retroreflectors are ideal where precision alignment is difficult or time-consuming. They feature three total internal reflections and will function even at very large angles of incidence. Zoolied supply 12.7mm 25.4mm 38.1mm 60mm corner cube prisms. Corner Cube Prisms,Corner Cube Retroreflectors,Corner Cube L Bar Prism,Optical Serveying Prism Zoolied Inc. , https://www.zoolied.com
