Variable Frequency Drive (VFD, frequency inverter, vvvf drive) Speed Torque Characteristics
In Constant Torque Area: Variable Frequency Drive (VFD, variable speed drive, VSD, frequency inverter) supplies rated motor nameplate voltage and motor develops full horsepower at 60 hertz base frequency.
In Constant Horsepower (hp) Area: Variable Frequency Drive (VFD, variable speed drive, VSD, frequency inverter, ac drive) delivers motor nameplate rated voltage from 60 Hertz to 120 hertz (or drive maximum). The motor horsepower (hp) is constant in this range. But the motor torque is reduced as frequency increases.
(Note: Motor Horsepower (hp) = Torque x RPM)
Below is the graph of Variable Frequency Drive (VFD, adjustable speed drive, ASD) Speed Torque Characteristics:
Blue = Horsepower
Red = Torque
Green = Motor Nameplate Frequency (60 Hz)
