An apparatus has a plurality of poles facing an air gap, and the poles are configured to generate a magnetic field in the air gap. The poles include a group of unchanged poles and a group of reversible poles, where a polarity of each reversible pole is configured to be changed during an operation mode, and after the polarity has been changed, each reversible pole and at least an adjacent unchanged pole in effect merged into one augmented pole, such that the pole number of the magnetic field in the air gap is changed.

An exciter comprises a stator armature defining a plurality of circumferentially spaced apart winding slots separated by respective stator teeth. first exciter winding with multiple phases, a second exciter winding with multiple phases. The individual windings of the first and second exciter windings are seated in the winding slots. For each phase of each of the first and second exciter windings there are two leads configured to connect to a generator control unit (GCU).

A rotor for an electrically excited drive machine includes: a coil per rotor pole with, in each case, one first energizable coil unit, and a rotor core for holding the coils of the rotor poles. The coils have, in each case, at least one second energizable coil unit per rotor pole. The rotor has an interconnecting unit which is designed to interconnect the at least two coil units per coil in a manner which is dependent on an operating point of the electric drive machine in order to set the number of windings of the coil, and in order to electrically connect the coils of the rotor poles for configuring a rotor winding with an overall number of windings which is dependent on the numbers of windings of the coils.

A rotor for an electrically excited drive machine includes: a coil per rotor pole with, in each case, one first energizable coil unit, and a rotor core for holding the coils of the rotor poles. The coils have, in each case, at least one second energizable coil unit per rotor pole. The rotor has an interconnecting unit which is designed to interconnect the at least two coil units per coil in a manner which is dependent on an operating point of the electric drive machine in order to set the number of windings of the coil, and in order to electrically connect the coils of the rotor poles for configuring a rotor winding with an overall number of windings which is dependent on the numbers of windings of the coils.

A solid-state electromagnetic rotor, including a plurality of salient pole pieces arranged around a supporting structure, wherein a first end of each salient pole piece is attached to the support structure and a second end of each salient pole piece points outward away from the supporting structure. The wires wound around each salient pole piece, wherein when the wires of the plurality of salient pole pieces are sequentially excited by an excitation circuit. The salient pole pieces are energized to provide a moving polar magnetic field in the form of distinct magnetic poles as desired to accomplish power generation.

In an assembly for electrically exciting the rotor of an electrical machine, the wear of the sliding contacts is reduced in operating conditions with low current density in that an AC current is injected. The additional injection of the AC current is superimposed upon the DC current. The rotor poles function as an open circuit with respect to the AC current through a co-rotating capacitor.

In an assembly for electrically exciting the rotor of an electrical machine, the wear of the sliding contacts is reduced in operating conditions with low current density in that an AC current is injected. The additional injection of the AC current is superimposed upon the DC current. The rotor poles function as an open circuit with respect to the AC current through a co-rotating capacitor.

In an assembly for electrically exciting the rotor of an electrical machine, the wear of the sliding contacts is reduced in operating conditions with low current density in that an AC current is injected. The additional injection of the AC current is superimposed upon the DC current. The rotor poles function as an open circuit with respect to the AC current through a co-rotating capacitor.

In an assembly for electrically exciting the rotor of an electrical machine, the wear of the sliding contacts is reduced in operating conditions with low current density in that an AC current is injected. The additional injection of the AC current is superimposed upon the DC current. The rotor poles function as an open circuit with respect to the AC current through a co-rotating capacitor.

A three-phase switched reluctance machine has a rotor, a first stator and a second stator. The rotor, first stator and second stator are coaxially and concentrically disposed. The rotor and both the first stator and second stator have corresponding poles. Only one of the stators has coils wound about its poles, while the other stator does not have any coils. A defined relationship between the number of rotor poles, the number of stator poles on the first stator and the number of stator poles on the second stator may improve the torque quality of the switched reluctance machine.