AC to DC Motor and Drive Conversions

The History There has always been a need for variable speed motors; dc motors were the first cheap, simple variable speed motors. They superseded NS motors, Schrage motors and eddy current drives with variator gearboxes trying to inefficiently compete mechanically. The dc motor offered a compact, relatively efficient reliable motor with good speed control and excellent starting torque. The trouble is they are expensive to buy, they are non-standard and expensive to maintain. They have…