摘要 |
A direct current dynamoelectric machine is disclosed including plural main poles on a field frame with a wound armature rotatably mounted therein. The main poles utilize high-strength permanent magnets which are thick enough to supply a magnetic field, but having means at an edge portion thereof (such as at the trailing edge on a D.C. motor) for increasing the air gap towards that edge to resist demagnetization resulting from armature reaction. Particularly, the permanent magnets of the main poles include a concentric portion of constant thickness and a flared portion of the same constant thickness, wherein the tangential manner. The dynamoelectric machine also includes permanent magnet interpoles between the main poles, wherein each permanent magnet for each interpole is supported nearby the armature surface by a means that is magnetically non-conductive so that flux from the permanent magnet interpole is limited by an effectively large air gap to a value appropriate for the strength of an interpole.
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