Abstract: This paper introduces the auxiliary generator in 30KVA rare-earth cobaltalternating current permanent magnet（PM） starter/generator. The solid rotor of the main generator is built by crosswise constructed rare-earth cobalt magnet steel which leads to a greater leakage flux.A toroidal armature's iron cone is set up in the flank of the solid rotor such that the leakage flux of main pole's flank can be used to generate the auxiliary generator. The design approach performance parameter differ from that of the main generator.