Common trouble shooting of distribution box

The distribution box is a large number of parameters on the data, which is generally composed of low-voltage forest. According to the electrical wiring, the switchgear, measuring instruments, protection appliances and auxiliary equipment are required to be assembled in closed or semi closed metal cabinet or on the screen to form a low-voltage distribution box. When the distribution box is in daily operation, with the passage of time, there will inevitably be failures, so for some common failures, some improvements can be made to the distribution box.

1. Adopt protection circuit to prevent external circuit fault of power supply of distribution box. Select a small volume of intelligent phase loss protector, such as da88cm-ii motor phase loss protection module, installed in the distribution box to prevent the motor from burning due to low-voltage phase loss operation.

2. If a new distribution stand on the column is added, 2mm thick stainless steel plate can be selected when making the shell of the distribution box, and the size of the distribution box can be appropriately enlarged according to the proportion, so as to increase the electrical safety distance between the outgoing lines of each branch, between the outgoing line and the shell of the box, which is conducive to the operation and maintenance of the agricultural electrician and the replacement of the fuse parts, as well as the heat dissipation.

3. Improve the wiring mode of the low-voltage capacitor bank of the original distribution box, and change its installation position from the pile head on the AC contactor to the connection between the low-voltage incoming line of the distribution box and the meter. In order to prevent the inaccurate measurement of the metering device due to the phase failure of the capacitor circuit or the damage of the capacitor in operation.

4. Selection of fuse. The rated current of the total overcurrent protection fuse at the low-voltage side of the distribution transformer shall be greater than the rated current at the low-voltage side of the distribution transformer, generally 1.5 times of the rated current, and the rated current of the melt shall be determined according to the allowable overload multiple and fuse characteristics of the transformer.

5. Selection of residual current action protector. Products conforming to IEC standards and certified by CNEEC must be selected. Similar to LJM (J) series power-saving and low sensitivity time delay protector can be selected.