Overview: AC drive being used in automation industries for about 20 years in China, due to the performance and impressive electricity saving rates, the rate of utilization reach 30 percent in different industries & applications, especially recent years, the annual growth rate is about 20%. AC drive in mine application is later than other applications, but in recent 5 years, the development is very fast and gonna be the head of other applications. The critical factor is the electrical equipments can't satisfy the requirements in industrial production, low efficiency and high energy consumption in old-fashioned equipments. Save energy and decrease carbon emission is necessary in current social development, our country pay more attention to anti-explosion AC drive in mine developing industry in this new trend.
1) It must be anti-explosion, the common AC drives can't operate as there are flammable & explosive gas, dust and humid environment. It needs put all of the components to a cabinet that comply with anti-explosion standard to ensure the variable frequency drive operation normally.
2) The distance between power source and variable frequency drive & motor is longer than normal applications, hence wastage is larger in normal three-phase four-wire 380V power supply. So, the voltage steps is 660V, 1140V, even 3300V, it relates to the equipment's horse power, below 100kW the voltage is 660V, 100 to 1000kW is 1140V, more than 1000kW the voltage is 3300V.
3) Strict requirement in anti-interference, the harmonic interference produced by AC drive should not affect other equipments operation after it's being used.
4) The specialization of the equipments in mine industry, such as long life time, reliable performance and other electric driving devices requirements.