Adjustable Speed Drives

Adjustable speed drives change the speed of a driven shaft to a speed selected by the operator.  Additionally, these drives are used to maintain the speed of a machine to very close tolerances: ±0.1% is not uncommon.  This is much more accurate than the speed control offered by conventional AC motors, which can vary 3% from no load to full.  Important performance specifications to consider when searching for adjustable speed drives include output shaft speed, output torque, continuous output power, and speed control.  The output shaft speed is the no load rotational speed of output shaft at rated terminal voltage.  Output torque describes the torque capability of the drive under constant running conditions.  The continuous output power is the mechanical power provided by the drive output.  Choices for speed control include handwheel, lever, screw, electric, and solid-state.