I. Introduction
Claw-pole alternators are widely used as generators in automobiles. The shape of the claws leads to a truly 3-D magnetic field in all regions. Consequently, for the correct calculation of magnetic field and alternator characteristics, a 3-D numerical method is required. The finite element (FE) method requires a large calculation time. The MEC method requires less calculation time and can retain high computational accuracy. Reference [1] gives performance computation results of a conventional claw-pole alternator using the 3-D MEC method.