Book - School of Science and Technology

Fan types and performance 479(a) (b) (c)(d)(e)Figure 17.5 Arrangements for centrifugal fans: (a) single inlet; (b) double inlet; (c) close-coupled withmotor; (d) flexible coupling in motor drive shaft; (e) belt drivenThe arrangement shown in Figure 17.5(e), where the motor drives the fan via pulleysand vee-belts, has the great advantage that the motor speed may be a standard, such as 16or 24 rev/s, whilst the fan speed is that best suited to the duty. A further advantage is thatif on testing it is found that the pressure loss of the system is less or more than allowed for,the fan duty may be corrected by merely changing the pulleys.