2.Type B: cantilever type, belt drive structure, belt wheel mounted between two supporting bearing seats. Suitable for medium and above centrifugal fans with variable speed.

3.Type C: cantilever type, belt drive structure, belt wheel mounted on the outside of the two supporting bearings. Suitable for medium and above centrifugal fan with variable speed, easy to disassemble with pulley.

4.Type D: cantilever type, transmission structure with coupling connecting the main shaft of the fan and the motor, the coupling is installed on the outside of the two supporting bearing seats, and the speed of the fan is the same as the speed of the motor. Suitable for medium and above centrifugal fans.

5.Type E: belt transmission structure, the two supporting bearing seats are mounted on both sides of the shell, that is, the impeller is placed in the middle of the two supporting bearings, for two supporting type, the pulley is mounted on one side of the fan. Suitable for double suction or large single suction and variable speed centrifugal fan, its advantage is more balanced operation.

6.Type F: transmission structure with coupling connecting the main shaft of the fan and the motor. The two support bearings are mounted on both sides of the casing respectively. It is suitable for centrifugal fans with double suction or large single suction and the same speed as the motor.