TRAPEZOIDAL FIELD POLE SHAPE IN SALIENT MACHINES

摘要

Salient pole motors and generators use a magnetic steel pole surrounded by an electrical winding to provide field excitation. The parallel sided shape of conventional field poles limit the amount of magnetic flux due to geometry and saturation constraints at the base of the pole. The base of the pole must carry the main flux plus the leakage flux. The optimum magnetic field pole shape is a trapezoidal configuration, that allows the flux density in the pole to be uniform. The base of the pole has a larger cross section to carry the main and leakage flux while the top of the pole is smaller to carry the main air gap flux.