1. Mine high and low voltage switchgear failure caused by ambient temperature:

The low-voltage electrical appliances in the mining high and low voltage switchgear are composed of fuses, AC contactors, residual current action protectors, capacitors and meters. These low-voltage electrical appliances are designed and manufactured in accordance with the Basic Standards for Low-Voltage Electrical Appliances, and their normal working conditions are specified accordingly: the upper limit of the ambient air temperature does not exceed 40. The average value of the ambient air temperature for 24h does not exceed 35, and the lower limit of the ambient air temperature is not less than -5 or -25. The switchgear of the rural network transformation is operated outdoors, it is not only directly irradiated by the sunlight to produce high temperature, but also produces heat in the operation, so in the high temperature season of midsummer, the temperature in the switchgear box will reach more than 60, and the temperature at this time greatly exceeds the ambient temperature specified by these electrical appliances, then the fault caused by the overheating of the electrical components in the switchgear will occur.

2. Failures caused by product quality:

In the transformation of the rural power grid, due to the demand for high and low voltage switchgear in the mine is very large, but the construction period is short, the distribution box manufacturers need to supply the low-voltage electrical appliances in a hurry and in large quantities, so there will be a phenomenon that the requirements for product quality are not strict, and then there will be a failure soon after the product is put into operation. For example, some types of AC contactors cannot operate soon after the distribution box is put into operation because the contactor closing coil is burned out.

3. Failure of high and low voltage switchgear in mining due to improper selection of electrical appliances:

Due to the improper selection of AC contactor capacity during manufacturing, AC contactors of the same capacity are installed for different outlet circuits, and the imbalance of three-phase load is not considered, and the current level of part of the outlet contactor is not improved on the basis of the normal selection model, which also leads to the burning out of AC contactors during operation in the high temperature season in summer. In the transformation of rural power grids, many of them are low-voltage electrical purchased by the state, and the quality requirements are not very high, and the general requirements are as long as they can be used. Therefore, users have a lot of problems in the process of using and spend a lot of money.

According to the above, we know the cause of the failure, then it is easy to do, for example, the first one is because of the influence of ambient temperature, then it is necessary to choose high-temperature resistant products or some cooling treatment in time according to the needs, and the second is that we must carefully review it before using it to determine that the quality is no problem in the purchase and use, and we cannot blindly choose. In addition, when we use the high and low voltage switchgear for mining, we should use it in accordance with the operation instructions, so as to reduce the occurrence of failures.