Abstract: A vector controlled system for two AC induction linear motors to effect dual axis planar motion. There are two or four motors located in a shuttle element. The element is mounted on a smooth face, which includes a glass surface on which the shuttle moves on an air bearing. Vector control for each of the motors accurately controls motor operation in a single axis. Accurate control of a shuttle is obtained in the orthogonal movement under the action of the motors which are respectively arranged for relatively orthogonal movement. Feedback means between the motors and linear scales formed in the backiron associated with the glass face facilitates the controlled positioning of the motors and the shuttle element on the glass face.

Abstract: A stepper motor includes a forcer wherein the teeth are formed in the pole faces by an etching process or machining and instepping. The etching can be achieved by forming the teeth in a separately formed plate which is anchored to the face of a forcer. A high density magnetic material is used for the plate and can also be used on the platen to improve performance of the stepper motor.

Abstract: A stepper motor includes a forcer wherein the teeth are formed in the pole faces by an etching process or machining and instepping. The etching can be achieved by forming the teeth in a separately formed plate which is anchored to the face of a forcer. A high density magnetic material is used for the plate and can also be used on the platen to improve performance of the stepper motor.

Abstract: A system for detecting movement of a forcer of a motor directed for effecting movement of a forcer in a first direction in response to command pulses. There is a toothed platen for locating the forcer so that the forcer is movable over the platen. A magnetic structure is attached to move with the forcer and has a periodic configuration corresponding to the forcer and in magnetic interchange relation to the platen. A magnetic circuit is associated with the magnetic structure. Flux sensors generate signal variations corresponding to flux variations as the forcer moves relative to the teeth of the platen. The signal variations provide step count signals, and the step count signals are compared to the command pulses to detect a disparity.

Abstract: A DC linear motor is cooled by providing a cooling duct extending transversely through the base mounting a coil. The coil is moveable along a track which is parallel to an extended permanent magnet. The cooling air is directed transversely along the width of the base. The compressed air passes through the duct and exits ports which extend transversely relative to the duct and the track. The air is ejected into the air gap between the permanent magnet and the coil.

Abstract: A bidirectional DC motor having a rotatable permanent magnet rotor structure within a ring core bearing helical windings is arranged to provide smoothly continuous torque over very wide excursion angles, which may be continuous if desired. Signals as to actual angular position of the rotor are utilized to generate timing signals for switching a driving current in proper polarity between different windings such that the extent and force of interaction fields remain substantially constant. The windings occupy different arc segments on the ring core and are energized such that all rotor tip regions are uniformly acted upon as the rotor moves from one arc segment to another.