Abstract: An electric motor generator system has a hollow rotatable shaft, a coil spar, and a plurality of magnet portions. The hollow rotatable shaft has a central longitudinal axis. The coil spar comprises one or more coil assemblies and is positioned concentrically within the hollow rotatable shaft. Each of the magnet portions is shaped to conform to a radially inwardly facing surface of the shaft. Each of the plurality of magnet portions abuts conformally against the radially inwardly facing surface of the shaft between the radially inwardly facing surface and the or each coil assembly.

Abstract: An electric motor generator system has a hollow rotatable shaft, a coil spar, and a plurality of magnet portions. The hollow rotatable shaft has a central longitudinal axis. The coil spar comprises one or more coil assemblies and is positioned concentrically within the hollow rotatable shaft. Each of the magnet portions is shaped to conform to a radially inwardly facing surface of the shaft. Each of the plurality of magnet portions abuts conformally against the radially inwardly facing surface of the shaft between the radially inwardly facing surface and the or each coil assembly.

Abstract: Electrical machine apparatus comprising: an elongate electrical conductor comprising a first part defining a first end and a second end, the first part defining a first conduit and a second conduit; a first coolant manifold arranged to provide coolant to the first conduit; and a second coolant manifold arranged to provide coolant to the second conduit.

Abstract: Electrical machine apparatus comprising: a first member comprising a ferromagnetic material and defining a first aperture arranged to provide a coolant to cool an electrical conductor.

Abstract: The purpose is to accommodate large axial channels in a slim electric machine without sacrificing its torque density and radial dimensions. This is possible with a rotor (11) provided with permanent magnets (12) and a stator (13) with slots (15) for coils (20A-c), where the slots (15) are separated by teeth (16, 17), which electrical machine include teeth (17) not carrying coils (20A-c), which teeth (17) are provided with axial channels (18, 18?) protruding into the teeth (17) and neighboring back iron so that an area of the channel (18, 18?) inside the tooth (17) is comparable to or even larger than the an area of the channel (18, 18?) in the back iron. The channels serve for transportation of fluids and other substances through the machine and also to integrate a motor protector, which may be required in down-hole applications. There are also novel manufacturing techniques associated with the new concept.