A motor drive controls the speed, torque, direction, and resulting horsepower of a motor. Dc drives typically control a shunt-wound dc motor, which has separate armature and field circuits. Ac drives control ac-induction motors and, like their dc counterparts, control speed, torque, and horsepower.

How does a DC drive change the speed of a motor?

Thus, the speed of a DC motor can be controlled in three ways: By varying the supply voltage. By varying the flux, and by varying the current through the field winding. By varying the armature voltage, and by varying the armature resistance.

How do industrial drives work?

An ac drive is a device that is used to control the speed of an electric motor. The speed is controlled by changing the frequency of the electrical supply to the motor. The three-phase voltage in the national electrical grid connected to a motor creates a rotating magnetic field in it.