Abstract In a DC dynamoelectric machine employing one or more commutating poles, machine performance and commutating ability with transient load conditions, cyclic pulsations in its power supply, or both, are enhanced by a commutating flux fidelity improvement winding. The winding comprises a quantity of low-resistance closed circuits equal to the quantity of commutating poles in the dynamoelectric machine. Each circuit encircles a commutating pole in its entirety and the proximate half of an adjacent main pole. A segment of each circuit is recessed in a face of one of the main poles adjacent a gap between the pole face and parallel to the axis of an armature rotatably supported in the machine. In response to load current changes in coils in the armature, distributed magnetic flux density changes occur at the gap. These flux density changes induce a voltage in the recessed segment, resulting in a current in the circuit. An additive flux is fostered in the commutating pole by this current in the circuit. The additive flux develops earlier than the normal commutating pole transient responsive flux. Since this additive flux occurs in advance of the normal commutating pole transient responsive flux, it is more nearly coincident with the causative transient condition and yields improved commutation in a dynamoelectric machine incorporating the flux fidelity improvement winding of this invention.
A DC dynamoelectric machine comprising: a generally tubular stator frame; a plurality of main field poles mounted in the stator frame to provide an appropriate first magnetic flux therein; each main pole having a recess provided centrally and axially in its inwardly directed arcuate face; a commutating winding mounted on at least one commutating pole in the stator frame, means for electrically connecting the commutating winding to a source of excitation current proportional to a load imposed on the DC dynamoelectric machine to yield a second magnetic flux cooperative with the first magnetic flux to improve commutation in the DC dynamoelectric machine; a commutating flux fidelity improvement winding mounted within the stator frame and having no electrical connections to a power source or load; said flux fidelity improvement winding comprising at least one low-resistance, closed-loop, electrically conductive circuit; said circuit including a plurality of conductive joined segments, at least one of said segments mounted in and projecting bidirectionally beyond the axial recess in one of the main poles and conductively joined at its projecting ends with other segments at each end, at least two of said other segments extended therefrom to terminate in free ends beyond an adjacent commutating pole, said free ends there conductively joined by at least one additional segment, said additional segment completing said electrically conductive circuit, said plurality of conductive joined segments providing a plurality of conductive turns at at least one pole of the machine; a gap adjacent said first segments of said circuits; an armature assembly rotatably supported in the stator frame for magnetic interaction therewith through the gap, and for rotation relative thereto, comprising armature coils, a magnetically permeable structure to retain the coils; a commutator and means for electrically interconnecting the coils and the commutator; and a suitable quantity of brushes resiliently biased into sliding engagement with the commutator to conduct electrical energy to he commutator for utilization in the armature coils connected to the commutator.
Claim 2
Dependent Claim
324 words
A DC dynamoelectric machine comprising: a generally tubular stator frame; a plurality of main field poles mounted in the stator frame to provide an appropriate first magnetic flux therein; each main pole having a recess provided centrally and axially in its inwardly directed arcuate face; a commutating winding mounted on at least one commutating pole in the stator frame, means for electrically connecting the commutating winding to a source of excitation current proportional to a load imposed on the DC dynamoelectric machine to yield a second magnetic flux cooperative with the first magnetic flux to improve commutation in the DC dynamoelectric machine; a commutating flux fidelity improvement winding mounted within the stator frame and having no electrical connections to a power source or load; said flux fidelity improvement winding comprising at least one low-resistance, closed-loop, electrically conductive circuit; said circuit including a plurality of conductive joined segments, at least one of said segments mounted in and projecting bidirectionally beyond the axial recess in one of the main poles and conductively joined at its projecting ends with other segments at each end, at least two of said other segments extended therefrom to terminate in free ends beyond an adjacent commutating pole, said free ends there conductively joined by at least one additional segment, said additional segment completing said electrically conductive circuit, said plurality of conductive joined segments providing a plurality of conductive turns at at least one pole of the machine; a gap adjacent said first segments of said circuits; an armature assembly rotatably supported in the stator frame for magnetic interaction therewith through the gap, and for rotation relative thereto, comprising armature coils, a magnetically permeable structure to retain the coils; a commutator and means for electrically interconnecting the coils and the commutator; and a suitable quantity of brushes resiliently biased into sliding engagement with the commutator to conduct electrical energy to he commutator for utilization in the armature coils connected to the commutator.