(Summary description)Wiring diagram of current transformer
Before the wiring diagram of the current transformer, let's take the ratio of the current transformer 200A to 5A as an example: the current flowing through 200A once, the current flowing through 5A twice is corresponding to the current flowing through 5A, and its "current changing ratio" is 200÷5 = 40 (times).
For this reason, the actual electricity consumption of the watt-hour meter is defined as the amount of electricity read by the meter (current month minus last month) ×40. Wiring diagram of ammeter and transformer on the distribution cabinet is as follows: 1. The above diagram is the wiring diagram of three current transformers; 2. The following diagram is the wiring diagram of two current transformers.
Ia+Ib+Ic=0 So: Ia+Ic=-Ib So: The green ammeter indicates the B-phase current.
The three-phase four-wire active watt-hour meter connected by current transformer shares the connection mode of voltage line and current line, which is quite a few in agricultural electricity metering. In this method, three voltage leads are eliminated, and the current transformer K1 is connected to the power supply L1. Through the current secondary line, the voltage pile head of the electricity hour meter and the current pile head are connected in a continuous way. This connection method aims to reduce the number of secondary wiring roots.
However, this method is very dangerous: first, the secondary circuit of the current transformer should not be grounded, otherwise, it will cause a short circuit and burn out the electricity meter. However, the regulations stipulate that the secondary loop of the transformer must be grounded at some point. Second, because the voltage and current terminals of the electricity hour meter and the secondary circuit of the transformer are all with 380/220V voltage, we should always pay attention to avoid accidental touch in the live work. Third, the zero line connected to the watt-hour meter should not be mistaken or replaced with any other one, otherwise the current coil of the watt-hour meter will burn out due to short circuit, and the current transformer will increase the circuit impedance infinitely and tend to open circuit due to the connection of the secondary circuit to the voltage coil of the watt-hour meter. All these are very dangerous.

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• Time of issue:2014-03-27 09:48
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