RPM 2 = reduced speed of driven equipment, in RPMįlow 1 = original flow provided by centrifugal fan or pumpįlow 2 = final flow provided by centrifugal fan or pump RPM 1 = original speed of driven equipment, in revolutions per minute (RPM) Hp 2 = driven-equipment shaft horsepower requirement at reduced speed

Hp 1 = driven-equipment shaft horsepower requirement at original operating speed Hp 2 = hp 1 x (RPM 2 /RPM 1) 3 = hp 1 x (Flow 2 /Flow 1) 3 For example, reducing speed (flow) by 20% can reduce power requirements by approximately 50%. Small decreases in equipment rotating speed or fluid flow yield significant reductions in energy use. The input power requirement varies as the cube or third power of the speed ratio. For centrifugal pumps or fans with no static lift, the fluid or air flow provided varies directly with the pump or fan rotational speed. PWM variable frequency drives are most often used in variable torque applications in the 1 to 1,000 hp motor size range. External sensors monitor flow, liquid levels, or pressure and then transmit a signal to a controller that adjusts the frequency and speed to match process requirements. Variable frequency drives efficiently meet varying process requirements by adjusting the frequency and voltage of the power supplied to an AC motor to enable it to operate over a wide speed range. A variable frequency drive (VFD) is a device that controls the rotational speed of motor-driven equipment.

Variable frequency drive 10 hp