An innovation has been made on the elevator transport system of Zhangcun Coal Mine of Lu′an Mining Industry Co.Ltd.

and a frequencyvariation speed control system has been designed for the rope-drawn rail vehicles.By adopting the technology of power frequency variation with the vector change control and real-time computer supervisory control

the innovation solves the problem of power level-free speed adjustment under the heavy load and long distance transport.The application of advanced technology can improve the transport function and the reliability and continuity of the system.The transport capacity has increased to 2.4 million ton a year from 1.5 million ton a year.