Test study on radiation electromagnetic disturbance of frequency conversionspeed control system applied to winch in underground coal mine

According to the radiation electromagnetic disturbance problems from the frequency conversion speed control and driving system of the winch in the underground coal mine, the paper analyzed the electromagnetic compatible radiation transmit limit of the frequency conversion speed control system as well as the underground mine test environment and test method. A site test was conducted on the electromagnetic radiation of the frequency conversion speed control system applied to the winch in the underground mine. The test results showed that the radiation electric field of the winch frequency conversion speed control system would be concentrated within 200 MHz, especially would be most obvious within 20 MHz, the radiation magnetic field would be concentrated within 2 MHz and the protuberance distribution of the low frequency sectional noise would be obvious. At a place with a distance of 1 m to the frequency conversion speed control equipment, the max value of the field strength in the measured radiation magnetic field was reached at 122.97 dBμV/m. The frequency spectrum of the radiation electric field in the winch electric motor was reached at 1 GHz, the radiation magnetic field was mainly concentrated within 50 kHz, but the total radiation strength was low and at a place with a distance of 1 m to the winch motor, the filed strength of the measured max electric filed would not be over 80 dBμV/m. Therefore, electromagnetic radiation disturbance of the winch frequency conversion speed control system was quite serious, would have a high influence to the radiation electromagnetic environment in the underground mine and would have disturbances to the monitoring and control equipment as well as the control system in the underground mine. The certain electromagnetic radiation disturbance restrain and shielding measures should be needed and conducted especially the place near the frequency conversion speed control equipment.