Radial forces between stator teeth and rotor claw inside a claw-pole alternator are investigated here. Typically three dimensional, the complete machine has been modelled as a coupled electric and magnetic circuit, with the aim of saving simulation time. Radial forces are obtained for several rotation speeds and stator currents. These results are compared with those of a 3D finite element analysis package, considered as reference results. A few typical results are also compared with measurements. Accuracy is sufficient to assess that the permeance network models, taking into account non linearities such as magnetic saturation, electronic commutations, and rotor movement, realise a good compromise between simulation time and precision.