the annual output of coal of a coal company of Shanxi Jincheng Anthracite Coal Mining Group is 600,000 tons, the belt conveyor in the coal outlet is driven by two sets 6kV / 710kW asynchronous motors. The enterprise originally adopts soft starters and hydraulic couplers to solve the problem of motor start and speed control, but there are still a lot of drawbacks. Soft starter will produce a large number of harmonics, hydraulic coupling has high failure rate with large maintenance works, and multi-motor drive is difficult to adopt liquid coupling to solve the power balance problem between two motors.
The FBDCZ in the mine ventilation opening of a coal mine of Shanxi Meijing Group is driven by two 10kV / 900kW asynchronous motors, the fan adopts industrial frequency constant speed drive, the air volume and negative pressure control is mainly achieved by adjusting the baffle position or fan angle, not only the energy waste is serious, and manually adjust the baffle or fan angle need to stop the machine, and remove the screws, which wastes time and effort and affects the production, and it’s easy to produce security risks once the screws are not tightened.
The underground drain pump in a mine factory of Guizhou Zijin Group is driven by a 10kV / 630kW motor, the capacity is mainly supplied by the on-site generator, the company uses the stator string reactor start mode, but still cannot fully meet the requirements. In addition, the scene needs to start and stop the motor according to the water level change, all day need someone on duty with large labor intensity.
In order to increase the daily processing capacity of ore, a tungsten plant in Ninghua Fujian has introduced a roller pressure system; the dynamic and fixed roller of roller press is respectively driven by two sets 10kV/630kW motors. At present, almost all the roller presses are constant frequency speed control, which results in the unadjustable output, and the over-current phenomenon caused by the imbalance of dynamic and fixed roller motor power.