3 Phase Drives
Many Hitachi drives are can be used in variable torque or constant torque mode.
Variable Torque(VT) mode will compensate for an increased/decreased base speed of a load. Variable torque loads will often decrease with the square of the speed. As the speed decreases the torque decreases with the square of the speed and the horsepower decreases with the cube of the speed.
Constant Torque(CT) mode keeps the torque the same regardless of speed. As the speed changes the horsepower will change in line with the speed. Constant torque loads will use a higher current at lower speeds than variable torque.