Cambridge Thermionic Corporation

Frank Lyman

Joseph Lyman

William C McDonald

A magnetic suspension system for efficiently supporting a rotor of relatively large radius and high available moment of inertia includes concentric stator and rotor elements spaced apart by narrow gaps of relatively large diameter and very small axial extent. A pair of spaced discs in the stator are oppositely polarized by a permanent magnet, their peripheral magnetic field strength being selectively augmented or diminished in predetermined sectors by electromagnet windings thereon. The rotor includes narrow ring faces juxtaposed to said discs, a permanent magnetic polarization being provided between the narrow ring faces. Means are provided for varying the relative electromagnetic contributions in the different sectors to maintain stability of rotor positioning with minimized electric power. SU

Magnetic suspension apparatus

A rotary stepping motor having high torque and low rotor inertia wherein the rotor is of a disk type configuration having a plurality of uniformly spaced rotor poles and the stator has a plurality of stator pole pairs which are formed in separate groups, the spacing between the stator poles in each group being equal to the rotor pole spacings and the spacings between the stator pole groups being not equal to the rotor pole spacings. The stator may be formed of laminated stator elements to provide a magnetic path with the laminations oriented so as to prevent delamination thereof due to the magnetic forces present during operation. The laminated stator elements are appropriately affixed to the motor housing so that the pole pieces thereof are maintained at preselected positions relative to a reference planar surface of the housing. The rotor poles may be tapered to further reduce the rotor inertia and increase motor speed operation.

Stepping motor

Rotor balancing apparatus and a system comprising balance probes for measuring unbalance at the ends of a magnetically suspended rotor are disclosed. Each balance probe comprises a photocell which is located in relationship to the magnetically suspended rotor such that unbalance of the rotor changes the amount of light recorded by each photocell. The signal from each photocell is electrically amplified and displayed by a suitable device, such as an oscilloscope.

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Cambridge, MA, United States of America

Frank Lyman