Abstract The performance and commutating ability of a dynamoelectric machine using commutating poles are improved during transient loading conditions and during pulsations in the power supply of the machine through the use of transient flux barriers which are mounted between the commutating pole piece and the commutating winding of the machine. Because the transient flux barriers are manufactured out of metallic material having a high level of conductance, transient leakage flux from the commutating pole induces eddy currents in the transient flux barrier. As a result, these eddy currents are prevented from being generated in the frame of the machine itself resulting in improved commutation while the current of the machine is undulating. The transient flux barriers have an extension at the end thereof adjacent the armature so as to have a substantially L-shaped cross section, and both the barriers and the commutating coil are positioned as close to the armature as is reasonably possible.
In a DC dynamoelectric machine having a stator including an annular stator frame and an armature mounted for rotation within said stator, commutation improvement means for substantially inhibiting changes in transient leakage flux, said commutation improvement means including a plurality of commutating pole assemblies each comprising: a commutating pole extending radially inwardly from said stator frame toward said armature, a pair of flux barrier elements formed of a nonmagnetic material having a high electrical conductance positioned on circumferentially opposite sides of said commutating pole, each of said flux barrier elements including a first portion abutting at least the radially inner portion of the respective side of said commutating pole and a second portion projecting tangentially away from said commutating pole at the radially inner end of said first portion such that said flux barrier element has a substantially L-shaped cross-sectional configuration, and a commutating coil surrounding said commutating pole and said first portions of said flux barrier elements, said second portions of said flux barrier elements and said commutating coil both being positioned as close to said armature as is reasonably possible.
Claim 2
Dependent Claim
182 words
In a DC dynamoelectric machine having a stator including an annular stator frame and an armature mounted for rotation within said stator, commutation improvement means for substantially inhibiting changes in transient leakage flux, said commutation improvement means including a plurality of commutating pole assemblies each comprising: a commutating pole extending radially inwardly from said stator frame toward said armature, a pair of flux barrier elements formed of a nonmagnetic material having a high electrical conductance positioned on circumferentially opposite sides of said commutating pole, each of said flux barrier elements including a first portion abutting at least the radially inner portion of the respective side of said commutating pole and a second portion projecting tangentially away from said commutating pole at the radially inner end of said first portion such that said flux barrier element has a substantially L-shaped cross-sectional configuration, and a commutating coil surrounding said commutating pole and said first portions of said flux barrier elements, said second portions of said flux barrier elements and said commutating coil both being positioned as close to said armature as is reasonably possible.