How to connect the three-phase four-wire trip switch of fee-controlled electric meter

Causes of tripping of three-phase four-wire leakage protector;

There are three main reasons for the tripping of leakage protector, namely overload, short circuit and leakage (the sum of current vectors is not zero). As long as the circuit has the above problems, the leakage protector will trip;

How to prevent the leakage protector from tripping due to overload, then we need to reasonably select the conductor of the circuit according to the electrical load and rationally configure the leakage protector according to the conductor. Only the matching circuit can prevent the leakage protector from tripping due to overload.

How to prevent the leakage protector from tripping due to short circuit, then we need to arrange the lines and wiring in strict accordance with the specification requirements, especially the handling of wire joints must be in place to prevent the virtual connection of wire joints and switches;

How to prevent the leakage protector from tripping due to leakage, then it is necessary to balance the insulation of the circuit and the three-phase load, which requires us to shake the insulation of the conductor after arranging the circuit and calculate the three-phase load to avoid the imbalance of the three-phase load;

The above is the method to prevent the leakage protector from tripping. By doing the above, we can basically avoid tripping the leakage protector.

Connection method of three-phase four-wire leakage protector;

Three-phase four-wire leakage protector, household miscellaneous altar, taking 4P leakage protector as an example to introduce you, 3P leakage protector.

4P leakage protector, the incoming terminal and outgoing terminal have four terminals respectively, that is, the incoming terminal has four terminals, the incoming terminal has L 1L2L3 and N respectively, and the outgoing terminal has the same terminals as L 1L2L3 and N;

When wiring, the yellow, green and red lines at the incoming terminal are respectively connected to L 1L2L3, the light blue line is connected to N, the yellow, green and red lines at the outgoing terminal are respectively connected to L 1L2L3, and the light blue line is connected to N. ..

Only the three-phase five-wire system can use leakage protection, while the three-phase four-wire power supply system (TN-C) in ordinary factories cannot use leakage protection devices, and ordinary factories use air switches. Starting with its principle, the principle of three-phase four-wire leakage protection is analyzed, and what is the trip of leakage protection and how to connect it.

This is the internal electrical schematic diagram of a three-phase four-wire leakage protection switch. You can see a current transformer in the lower left corner. Both the three-phase line and the neutral line pass through the inner ring of the transformer. This loop can be understood as a device made of some magnetic material, which can effectively sense the sum of current changes on the four main lines. According to the law of electromagnetism, as long as the sum of currents changes, there will be a changing magnetic field in the ring, and then a measuring coil will be wound around the ring. The changing magnetic field will induce electromotive force on the coil, so that there are voltages at the A and B terminals on the diagram.

Generally speaking, according to the current node law, no other branch generates current, and the vector sum of the current flowing into the ring and the current flowing out of the ring is 0, that is, there is no changing magnetic field on the ring, the coil wound on the ring has no induced electromotive force, and there is no voltage across A and B.