In the application of Air Supply Unit (ASU) high power rating three phase induction motor is used. The electric drive systems used in industrial applications are increasingly required to meet the higher performance and reliability. Today about 90% of all industrial motor applications use three phase induction motors because they are simple in design, easy to maintain, and are less costly than other designs. The traditional method of such flow control of ASU is use an induction motor run at

more »

... ant speed with 50-Hz power supply and then control the flow by means of a throttle. As per the fan affinity law where the load torque and power vary with the square and cube, respectively of the speed. If reducing RPM by 10% decrease the power requirement by 27%. This change gives a large power reduction compared to fixed-speed operation. Relatively small reduction in speed gives large saving in energy consumption. Also by Using a variable frequency drive to control the air flow with a fully open throttle saves a considerable amount of power. The ASU does not need to be run at full speed throughout the day and therefore, a variable frequency drive can be employed to reduce the ASU motor speed. The main aim of this paper is to reduce the energy consumption by the implementation of VFD. Hence the proper control of air flows is achieved and increases the motor life. For the flow control with energy saving in centrifugal fan we propose to use variable speed drive.