Abstract: In a brushless generator having an exciter rotor (18) which generates an AC voltage that is rectified to provide a DC field for a main generator rotor (16), the rectifiers are mounted to revolve with the rotor and be fluid and conductively cooled to provide a dynamo operative without brushes, slip rings or commutators. The rectifier is formed by a diode assembly (24) including layers of insulating and conducting material that are mounted concentrically on the inside wall of a hollow rotor shaft (20) so that diode chips are stressed only in compression due to centrifugal forces of rotation. An input driven shaft (32) may be accommodated interiorly of the diode assembly (24) along the axis of the hollow rotor shaft (20). The dynamo electric machine may also be operated as a brushless motor.

Abstract: An undesirably long brushless generator including a permanent magnet generator 114, 116, 118, an exciter 64 and a main generator 22, 24, 42, 44 may have its axial length reduced by locating both the permanent magnet generator 114, 116, 118 and the exciter 64 adjacent one end of the main generator 22, 24, 42, 44 in an essentially coplanar relation with the permanent magnet generator 114, 116, 118 radially inward of the exciter 64.