Motor Controllers

Motor controllers receive supply voltages and provide signals to motor drives that are interfaced to motors. They include a power supply, amplifier, user interface, and position control circuitry. Motor controllers are used with several types of motors. Brushed motors commutate with physical contacts. Brushless motors do not. For example, induction motors induce current into the rotor windings without any physical connection to the stator windings. Synchronous motors, no-slip devices that operate at constant speed up to full load, include both reluctance motors and servomotors. Pole changing motors (PCM) use pole number control, a method for changing the number of poles on the primary winding. Vector drive motors provide independent control of both the voltage and frequency. In some designs, encoders or resolvers are used to provide feedback about position and speed. Linear motors generate force in only the direction of travel. Common technologies include moving coil and moving magnet designs. Many types of stepper motors use motor controllers. Examples include full-step motors, half-step motors, mini-motors, micro-motors, unipolar stepper motors, and bipolar stepper motors. Motor controllers are also used in pneumatic and hydraulic motion control systems.