Abstract: A stator coil assembly comprising a stator coil and a mounting platform for the stator coil. The coil has an earth wrap and is bonded to the mounting platform by a resiliently deformable bonding layer. The bonding layer is an electrical insulator formed from silicone rubber and has a thermal conductivity of at least 0.1 W/mK and an electrical resistivity which is at least equal to that of the earth wrap.

Abstract: A rotor disc (14), for use in an electrical machine (10), has at least one circumferential rotor rim (16) mounted thereon. The rotor rim (16) comprises at least one row of alternate magnets (20) and laminated pole pieces (18). The laminations in each pole piece (18) are mounted concentrically on a bolt (22) that extends through the rotor disc (14). A clearance (23) is provided between the laminations in each pole piece (18) and the bolt (22). The clearance (23) insulates the bolt (22) from the laminated pole pieces (18), which are made from a ferromagnetic material such as silicon-iron alloy, to minimize power losses due to eddy currents.

Abstract: A rotor disc (14), for use in an electrical machine (10), has at least one circumferential rotor rim (16) mounted thereon. The rotor rim (16) comprises at least one row of alternate magnets (20) and laminated pole pieces (18). The laminations in each pole piece (18) are mounted concentrically on a bolt (22) that extends through the rotor disc (14). A clearance (23) is provided between the laminations in each pole piece (18) and the bolt (22). The clearance (23) insulates the bolt (22) from the laminated pole pieces (18), which are made from a ferromagnetic material such as silicon—iron alloy, to minimize power losses due to eddy currents.

Abstract: Hardness testing apparatus, for use in assessing dimensions, from which a hardness value can be determined, of an indentation formed under controlled conditions in a surface of a specimen, having a photosensitive detector for sensing brightness over an image in which the indentation differs in brightness from the rest of the image. The detector produces electrical signals representative of sensed brightness. Discrimination circuitry discriminates signals representative of brightness within the indentation from signals representative of brightness outside the indentation. Correlation of discrimination results provides an assessment of indentation dimensions. Preferably oblique lighting is used to provide enhanced brightness differentation between a multifaceted indentation and other specimen surface features. The oblique light is directed so as to be specularly reflected from a facet of the indentation vertically with respect to the general specimen surface.

Abstract: Hardness testing apparatus, for use in assessing dimensions, from which a hardness value can be determined, of an indentation formed under controlled conditions in a surface of a specimen, having a photosensitive detector for sensing brightness over an image in which the indentation differs in brightness from the rest of the image. The detector produces electrical signals representative of sensed brightness. Discrimination circuitry discriminates signals representative of brightness within the indentation from signals representative of brightness outside the indentation. Correlation of discrimination results provides an assessment of indentation dimensions. Preferably oblique lighting is used to provide enhanced brightness differentation between a multifaceted indentation and other specimen surface features. The oblique light is directed so as to be specularly reflected from a facet of the indentation vertically with respect to the general specimen surface.