Cement plant is a big power consumer, in recent years the application of frequency converter project is expanding day by day. Mainly vertical kiln Roots blower, garden disk feeder, pre-added water into the ball, screw conveyor, crusher, crusher, belt conveyor, as well as exhaust fans and so on. After the application not only saves electricity expenses, and improve product quality, but also increase the flexibility of use, for different process requirements adaptability is stronger. Therefore, many vertical kiln cement plants have been selected frequency converter on the kiln, especially the Roots blower technology transformation, have received a very significant economic results, power saving rate of up to 30% -50%, changed the past to adjust the outlet (inlet) valve openings to regulate the wind pressure or air volume of the production mode, reduce labor intensity, adjust the timeliness of the good, improve the product's qualification rate, the unit of consumption has decreased significantly.