Non-destructive Measurement of Magnetic Properties of Claw Pole

Abstract The magnetic properties of the claw pole have a direct effect on the output power of a generator. Many methods can be used to measure these magnetic properties, each with its own advantages, but an important shortcoming is that all are destructive. In this study, a new non-destructive method to measure the magnetic properties of claw pole was proposed and a corresponding testing set-up was designed. A finite-element model was constructed to simulate the measurement process. Results proved that the measured magnetization-like curves had good agreement with the trend of the input magnetic curves and the effect of the positioning error in the measuring process could be neglected. To further validate the new method, seven types of claw poles of different materials subjected to different heat-treatment processes were forged and tested by both the new method and the conventional ring-sample method. Compared with the latter, the new method showed better consistency, relatively higher accuracy, and much stronger stability of measurement results; however, its sensitivity needs to be improved. The effects of material compositions and heat-treatment parameters on the magnetic properties of the claw pole were briefly analyzed.