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.
Master and slave control to achieve the power balance of two motors;
Realize the soft start and soft stop of belt conveyor, without impact current, reduce the damage to belt;
Low frequency large torque characteristics of the mv vfd to meet the heavy load start of belt conveyor;
Equipment maintenance cycle is extended, maintenance costs is reduced;
System efficiency is improved with certain energy saving effect.