S p systems offers supplies specialised solutions for applications like centrifugal fans, pumps and blowers. The ac variable speed drivesvariable frequency drive controls the flow of any centrifugal fan or pump directly by controlling the speed of its ac motor. This which is the most efficient means of capacity control. Controlling the speed of the centrifugal loads will significantly reduce the energy consumption. The change in flow rate is directly proportional to the change in motor speed. But the horse power required to drive the fan varies with the cube of the motor speed. Any other method of flow control does not fully utilize on this important relationship, ie, 80% of flow the hp consumption will be a cube of [0.8]=0.512=51.2% only, whereas with conventional throttling or damper method for these loads, consumption is nearly 80%. Other advantages: the power factor will be always > 0.96,. Soft start-provides smooth acceleration and limits high in rush current, motor gets all protection electronically, process control will be more precise and accurate.
