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1、低压配电装配小记（Low voltage power distribution assembly C.）When a.Txt low voltage power distribution assembly you were born, you were crying and everyone around you was smiling; when you are passing away, youre smiling but lookers on are crying! Love someone an hour to take only a day to love someone, but
2、it takes a lifetime to forget someone with a three-phase five wire color is yellow, green, red, light blue, V, W, U N double color protective grounding wire (PE) respectively.Transformer in operation, the transformer phase current should not exceed the rated current; the maximum unbalanced current s
3、hall not exceed 25% of the rated current. Transformer should be checked regularly after putting into operation.In the system supplied by the same transformer, it is not suitable to protect the ground and protect the connection with zero.The rated voltage of the two coil of the voltage transformer is
4、 generally 100V.The two side of the voltage transformer shall not be short circuited during operation. Due to the short circuit will produce a large short-circuit current, it may burn out the transformer, therefore, once the voltage transformer, the two side are equipped with fuses for protection.On
5、e side of the two side of the voltage transformer must be grounded. This is to prevent the first and two coil insulation breakdown, a high pressure into the two side, endangering the safety of the human body and equipment.When the current transformer works, the two side is close to the short circuit
6、 condition. The rated current of the two coil is generally 5AThe two side of the current transformer must not be allowed to open when operating,The two side of the current transformer has to be grounded at one end to prevent the one or two side winding from breaking into the two side when the insula
7、tion is broken.When the current transformer is connected, it should pay attention to its polarity of the one or two coil, and the method of polarity reduction is used in the transformer of our country.Installation must pay attention to the wiring is correct and reliable, and the two side is not allo
8、wed to fuse or switch. Even if, for some reason, the instrument or other device on the two side is to be dismantled, the two side must be short circuited and then removed.Low voltage switch refers to disconnecting switch, circuit breaker, fuse and so on under 1KVThe load controlled by the low voltag
9、e distribution equipment must be clear shunting, and it is forbidden to control and confuse one gate.The interlocking device of low voltage distribution equipment and self-contained generator equipment should be reliable. Prohibit self owned power generation equipment and power grid parallel operati
10、on without authorization.Insulation pads should be laid on the passageway for the left and right operation and maintenance of the low voltage distribution device, and other items are not allowed to be piled on the channel.When the equipment is connected, the equipment is connected first and then the
11、 power supply is connected.When dismantling equipment: first disassemble the power supply, and then dismantle the equipment.When connecting the line: first connect the zero line, then connect the fire line.When dismantling the line: first dismantle the fire line, and then dismantle the zero line.Low
12、 voltage fuse can not be used as overload protection of motor.The rated voltage of the fuse must be greater than the working voltage of the distribution line.The rated current of the fuse must be greater than or equal to the rated current of the melt.The breaking capacity of the fuse must be greater
13、 than the maximum short-circuit current that may occur on the distribution line.The selection of the rated current of the melt must meet the normal working current of the line and the starting current of the motor.For the short circuit protection of electric furnace and lighting, the rated current o
14、f the melt is equal to or slightly greater than the rated current of the load.For a single motor, melt over rated current (1.5-2.5) motor rated currentThe rated current of the melt should be coordinated in the distribution system, so as to achieve the purpose of selective protection. The next level
15、should be smaller than the previous level.Porcelain plug fuse should be installed vertically, must adopt qualified fuse, not with other copper wire instead of fuse.Power screw type fuse into the line should be in the center of the terminal base on the load line terminal should be connected to the sc
16、rew shell.When the melt is replaced, the electric equipment must be disconnected so as to prevent the arc from being producedThe fuse shall be installed on each phase line. No fuse can be installed on neutral line of two-phase three line or three-phase four wire circuitFuses are mainly used for short circuit protectionWhen fuses are used for isolation purposes, fuses
