Calculation and measurement of time characteristics of local field quantities in the air-gap of claw-pole alternators

This paper deals with the calculation and measurement of local magnetic field quantities in the air-gap of claw-pole alternators. The numerical procedures are based on 3-D finite element methods (FEM). It is important to investigate the local field and force-density distribution on the surface of the stator in order to use these results for dynamic mechanical displacement calculations. This is the basis for acoustic prediction of the audible noise. The calculation method is presented for global values, like induced voltages, and for local time characteristics, like force-densities and flux-densities. The inductions on the stator surface are measured using thin Hall effect devices at different stator tooth positions. All presented results are compared with measurements on a simplified test-alternator and show good agreement.