Variable Frequency Drives (VFDs)


A Variable Frequency Drives (VFDs) also known as adjustable-frequency drives, are a type of AC (Alternating Current) electric motor controller that adjusts the rotational speed (rpm) of the motor. Having the ability to change the motor speed allows for more control of the motor’s power delivery to the grinder rotor or chipper disc.  The VFD changes the input frequency (Hz) and voltage to change the speed. An equally important feature of a VDF is that it can limit electrical demand, or spikes that a large load on the rotor or disc can create.  This feature may reduce the electrical cost of operating the machine.

Peterson offers either a VFD or soft start option for the main rotor drive motors for most of electric grinders. VFDs are more expensive, and more complicated, but they allow more control over the motor’s speed and power output.

Peterson electric chippers and grinders can be controlled with either soft starts of VFD (variable frequency drives). VFD’s can provide variable speed that can be used to optimize the end product quality and production. They can also be programmed to limit peak power (typically 150%) which can help reduce the utility bill. VFD’s can cause electrical “noise.” Some Utilities will require additional conditioning filters. VFD’s also have a finite life and require added cooling in the control room.