An axial electromagnetic bearing for smooth shafts of large diameter and relatively shorter length of the type comprising a stator of substantially annular shape and an armature in the shape of a disc attached to the shaft and located facing the stator, at least one axial position detector for the shaft being associated with the axial bearing, and the bearing being characterized in that the stator of the axial bearing is composed of four independent sectors each of which comprises a ferromagnetic core and a winding and each of the independent sectors of the stator of the axial bearing being controlled by at least one corresponding detector determining the axial position of the shaft in relation to the said sector.

An active type magnetic bearing for controllably supporting a rotatable shaft made of a magnetic material is constructed such that a stator made of an annular formed laminated iron core is provided around the rotatable shaft, a number of slots are formed along an internal surface of the iron core, stator windings of a number of phases are wound so as to be settled in the slots, thin sheet-like permanent magnets magnetized radially to provide a number of poles are secured onto the internal surface of the annular formed iron core with a predetermined air gap maintained between the permanent magnets and the rotatable shaft, and the stator windings of each phase are so wound that upon energization, a magnetic field thereby produced enhances a magnetic field produced by one of the permanent magnets while it reduces a magnetic field produced by another permanent magnet provided at a position 180.degree. spaced apart from that one of the permanent magnets.

A rotor armature assembly for an electromagnetic radial bearing for use in high rotational speed applications comprises a rotor armature fixedly connected to a rotor shaft. The rotor armature is formed of a plurality of annular magnetic plates each comprised of soft magnetic material, and a plurality of annular reinforcing plates each comprised of material having greater tensile strength than the soft magnetic material. The reinforcing plates are interposed between the magnetic plates and all of the plates are axially urged together so that adjoining plates are in frictional engagement with each other to form a laminated plate structure. The reinforcing plates frictionally restrain radial outward deformation of the magnetic plates due to centrifugal force during high speed rotation of the rotor armature assembly.

This invention relates to a device for measuring the induction in the air gap of a magnetic bearing, which comprises an assembly of small notches of small width made in the longitudinal direction of the rotor and distributed on the periphery thereof, an assembly of small coils disposed in the end faces of the poles of the stator frame located opposite the rotor, parallel to said small notches, and means for detecting the alternating voltage induced in each small coil due to the passage of the small notches of the rotor opposite said small coils.

Electromagnetic damping techniques for use in slowing down the shaft to a gas turbine based on various electrical machine concepts. A rotor may be mounted on an outer race of a bearing through which the shaft extends. The damper may use a permanent magnet (PM) design with permanent magnets mounted to the rotor. Alternately, the rotor and stator may be designed to operate upon a switched reluctance motor (SRM) design. Instead of having the rotor mounted to the outer race, an alternate arrangement may use a rotor mounted directly to the gas turbine shaft in which case the rotor and a corresponding stator serve both as a damper and as an electrical generator for providing the usual electrical generation functions from the gas turbine shaft.