Large Adjustable Speed Fan Drives Including Static Converter Developments for Cement Plants

The continuing need for more efficient and productive process units has caused the cement industry to seriously consider larger better performing fan drives. Fans now being used in studies range up to 3500 hp, and an 1800-hp dc fan drive is on order. With the increased horsepower requirements and higher power rates, operating costs need to be carefully evaluated in the drive selection. In addition, drive performance characteristics are important. Fan characteristics and the different methods of obtaining adjustable flow are reviewed. The efficiency advantage of all-electric type speed control is emphasized, but other aspects and other drives are covered.