Direct current dynamoelectric machines utilizing high-strength permanent magnets

A direct current dynamoelectric machine comprising:

• a field frame of magnetic flux conductive material having means for establishing a magnetic field within said field frame provided on at least two main poles;
• and
• an armature rotatably disposed within said field frame having an armature winding thereon, said armature defining an air gap between an outer surface thereof and a pole face of each of said main poles,
• wherein said means for establishing a magnetic field includes a plurality of high-strength permanent magnets with one permanent magnet for each of said main poles, each permanent magnet being of substantially uniform thickness throughout including a concentric arc portion that is substantially concentric along its face with said armature outer surface and a means for increasing the air gap between the armature and the main poles at an edge portion of each of the permanent magnets subject to a demagnetization force when said machine is loaded for resisting said demagnetization force, and further wherein each permanent magnet includes a flared portion at said edge portion as said means to increase the air gap.

A direct current dynamoelectric machine comprising:

• a field frame of magnetic flux conductive material including means for establishing a magnetic field within said field frame, said means including at least two main poles;
• an armature means rotatably disposed within said field frame including an outer surface, which defines an air gap with faces of said main poles;
• and
• interpole means for improving commutation characteristics of said dynamoelectric machine connected to said field frame in at least one commutating zone between said main poles, said interpole means comprising a permanent magnet and means for providing an effective air gap between said permanent magnet and said field frame for restraining the amount of flux that the permanent magnet transmits to the field frame.

A direct current dynamoelectric machine comprising:

• a field frame of magnetic flux conductive material having means for establishing a magnetic field within said field frame provided on at least two main poles;
• and
• an armature rotatably disposed within said field frame having an armature winding thereon, said armature defining an air gap between an outer surface thereof and a pole face of each of said main poles,
• wherein said means for establishing a magnetic field includes a high-strength permanent magnet provided on each pole face of said main poles, each permanent magnet being of substantially uniform thickness throughout including a concentric arc portion that is substantially concentric along its face with said armature outer surface and a means for increasing the total of air gap and magnet thickness between the armature and the pole face of each main pole at an edge portion of each of the permanent magnets subject to a demagnetization force when said machine is loaded for resisting said demagnetization force, and further wherein said means for increasing the total of air gap and magnet thickness comprises a flared substantially flat surface on said pole face of each of the main poles beneath said edge portion of each of the permanent magnets to form an increasing gap toward the edge thereof and to increase the total of air gap and magnet thickness between said armature and said pole face of each of said main poles.

A direct current dynamoelectric machine comprising:

• a field frame of magnetic flux conductive material including means for establishing a magnetic field within said field frame, said means including at least two main poles;
• an armature means rotatably disposed within said field frame including an outer surface, which defines an air gap with faces of said main poles;
• and
• interpole means for improving commutation characteristics of said dynamoelectric machine connected to said field frame in at least one commutating zone between said main poles, said interpole means comprising a permanent magnet and including a non-magnetic support means between said permanent magnet and said field frame.