Abstract: A rotary electrical machine comprises a rotor assembly and a stator assembly separated by an air gap. The stator is formed from discrete generally pie-shaped pole pieces having a progressively increasing radial slot to accommodate winding of the coil. The pole pieces are preferably wound from a grain oriented ferromagnetic tape to improve the permeability of the pole and its saturation level. Groups of poles may be separated into sectors. In an alternative embodiment, at least some of the pole pieces are formed from both a permanent magnet and ferromagnetic tape to provide a constant bias between the rotor and stator assemblies.

Abstract: A magnetic bearing has a number of pole pieces disposed about the circumference of the shaft supported by the bearing. To inhibit magnetic flux migration within the bearing, magnetic barriers of non-magnetic material are interposed between pole pieces at selected locations. Magnetic guides prevent magnetic saturation of the bridging portion of the pole pieces prior to the poles' saturating.

Abstract: A gas compressor, particularly of the kind for boosting pressure in gas transmission and petro chemical process, has an impeller mounted on an impeller shaft of the overhung type mounted on front and rear bearings and having at least one impeller mounted between the front bearing and a front end of the shaft. Annular seals are provided co-axial with the shaft which separate an inner space communicating with the shaft front end from the suction end gas space which lies outside the seals. The seals include an outer seal and an inner dry gas seal. Pressurized process gas is supplied between these seals at a pressure higher than suction pressure and is vented from the inner gas space at a pressure well below suction pressure to limit gas pressure forces on the front end of the shaft.

Abstract: A gas compressor, particularly of the kind for boosting pressure in gas transmission lines, has an impeller mounted on a shaft located between two bearings with the gas space surrounding the impeller being separated from the bearings by dry gas seals, including a least primary dry gas seals. The primary dry gas seal adjacent the discharge end of the compressor is of larger diameter than the corresponding seal at the inlet end of the compressor so that pressurized gas acting on the respective rotary parts of the dry gas seals urges the shaft towards the discharge end of the compressor and thus counteracts dynamic forces on the impeller.