AC generator has a concentric coil on its frame side and two rotors rotating concentrically with different RPMs one at high-speed with permanent magnets and one at a slower speed made of solid metal.

摘要

A fixed laminated iron core (1) supports a concentrically wound coil (2). A shaft (4) rotating at low RPMs fits in the iron core concentric with a first bearing (3). An inner rotor (5) cast from metal like a bell fastens on the shaft. A second bearing (7) with the inner rotor running at lower RPMs also fits on the shaft to support an outer rotor (6) running at higher RPMs. On the outer rotor's inner sleeve side there is a laminated, slotted iron core (8) with radially magnetized permanent magnets in its slots.