The Difference is in the Name

Variable Speed Motors

Variable Speed Motors are AC motors that can operate within a range of different speeds. The most common type of Variable Speed Motors have a combination of an AC motor and an Eddy Current (DC) Clutch. Dynamatic is the largest manufacturer of AC Eddy Current motors. Variable Speed motors are used on punch presses, air handling equipment, mixers, etc. This type of motor is manufactured by General Electric, Louis-Allis, US Electric, and Westinghouse. Variable Speed motors are very expensive and are being obsoleted by Variable Frequency Drives.