Abstract: A core for a multi-phase transformer includes a body made of two or more rings having a common central axis. Each ring consists of a strip of magnetic permeable material wound about the central axis. The body is provided with a plurality of radially disposed windows, each window being bound by opposed axially extending legs and opposed circumferentially extending branches. The branches of each window are provided in respective axially adjacent rings, so that the branches and legs of each window define a closed magnetic circuit of substantially uniform magnetic permeability through which magnetic flux can circulate about the windows.

Abstract: A core for a multi-phase transformer includes a body made of two or more rings having a common central axis. Each ring consists of a strip of magnetic permeable material wound about the central axis. The body is provided with a plurality of radially disposed windows, each window being bound by opposed axially extending legs and opposed circumferentially extending branches. The branches of each window are provided in respective axially adjacent rings, so that the branches and legs of each window define a closed magnetic circuit of substantially uniform magnetic permeability through which magnetic flux can circulate about the windows.

Abstract: An electric motor 10.sub.vi includes a Cockcroft ring 12 for producing a magnetic field having lines of flux extending in the first direction through an air gap 18. A disc 14 capable of at least two dimensional motion in a plane relative to the Cockcroft ring 12 provides a plurality of conductive paths C.sub.A -C.sub.E. Each path C.sub.A -C.sub.E has a segment 16.sub.A -16.sub.E respectively that extends through the magnetic field in a second direction so that interaction with an electric current passing through a particular segment 16.sub.A -16.sub.E, produces a thrust force acting on the disc 14 via that segment 16.sub.A -16.sub.E. A multi phase toroid shaped transformer 40 induces electric currents to flow in the paths C.sub.A -C.sub.E and thus through the corresponding segments 16.sub.A -16.sub.E. One of the segments, for example 16.sub.A is located relative to a second segment for example 16.sub.E, so that their respective thrust forces do not lie in the same axis.