Title: Operation method of three-phase meter connection
Tags: 3 phase electricity meter
Blog Entry: 1. Direct access method If the power of the three phase meter  is within the allowable range of the watt-hour meter, then the direct access method can be used. 2. When the electricity meter is used to measure the power consumption of a large-current three-phase circuit through the transformer access method, because the current flowing through the line is very large, such as 300-500A, it is impossible to use the direct access method, and the current should be used The transformer performs current conversion, converting a large current into a small current, that is, the current that the watt-hour meter can withstand, and then measuring. Generally speaking, the secondary side current of the current transformer is 5A, such as 300/5,100/5. Note: The K2 terminal of the current transformer is grounded instead of the neutral wire. There are the following precautions when connecting the meter 1. The meter line of the low-voltage electric energy meter adopts an insulated copper core wire with a rated voltage of 500V. The current carrying capacity of the wire matches the load, and the wire section is not less than 2.5 square millimeters. 2. The laying of plastic insulated wires should be laid by wire codes, plastic slot plates or plastic pipes. 3. The phase sequence of the meter wires of three-phase three-wire and three-phase four-wire electric energy meters should be marked with yellow, green, and red wires or yellow, green, and red colors should be painted on the wires to separate the phase sequence. If the neutral wire is black No color is applied. 4. When connecting the primary wire of the low-voltage current transformer, pay attention to the number of turns and joints of the marked transformation ratio. The meter wire should be crimped to the lug. 5. The wiring of the watt-hour meter should be based on the drawings attached to the meter and the wiring diagram on the back of the meter cover, which is for the new meter. Be especially careful with the old watch. The wiring diagram on the back of the watch cover may be inaccurate, because you don't know whether the watch cover is the original one for the watch or it may have been changed unintentionally. To be on the safe side, use a multimeter to actually measure it to find out the terminals connecting the current coil and voltage coil. Generally, the resistance of the voltage coil is 700-800 ohms, and the resistance of the current coil is 0 ohms. Failure to do this step may cause a short circuit failure. 6. When connecting a three-phase four-wire watt-hour meter with a current transformer, the three voltage coil connecting pieces on the watt-hour meter should be removed. If it is not removed, it will cause a short circuit. 7. The polarity of the current transformer must be connected correctly. When the wire of the main circuit passes from the P1 end to the P2 end, the k1 on the secondary side of the transformer should be connected to the 1, 4, and 7 terminals of the watt-hour meter, and the k2 should be connected to the 3, 6, and 9 terminals. If k1 and k2 are all reversed, either do not turn or reverse. If only one or two of them are connected reversely, the 3 phase electricity meter  will measure less electricity.