VARIABLE SPEED AC MOTOR DRIVE DEVICE

摘要

A low cost, small rating AC motor drive includes an inverter in which static controlled switches are in two sets associated with opposite poles and controlled in such a way that current continuously fed is sensed relative to one set for feedback current sensing and that the switch current is modulated in the other set in order to regulate the motor current. When starting, or overloaded, the motor drive speed is automatically reduced under air gap motor sensing.