Eddy-current computation in the claws of a synchronous claw-pole alternator in generator mode

This paper deals with the three-dimensional finite-element (FE) calculation of eddy currents in the claws of a claw-pole alternator taking the rotational geometry movement into account. For this calculation a transient edge-based A/spl I.oarr/, A/spl I.oarr/ - T/spl I.oarr/ formulation is utilized. The generation of the FE model with a special focus on the discretization of eddy-current regions and air gap is presented. The main intention lies in determining the eddy-current losses in the rotor claws in generator mode at constant speed. Since high-speed and high material conductivity leads to divergence, under-relaxation of the material conductivity in the claws is conducted.