Note that the following three pages are for the coaxial counter rotating configuration [rotor - stator - rotor]. [Source ~ PMMT p.336], and Permanent Magnet Motor Technology.pdf ~ in hard drive

An axial flux PM motor can be designed with the counterrotation of two rotors [ U ] . This machine topology can find applications in ship propulsion systems which use an additional counter-rotating propeller in order to recover energy from the rotational flow of the main propeller stream In this case the use of an axial flux motor having counter-rotating rotors allows t,he elimination of the motion reversal epicyclical gear. The stator winding coils have a rectangular shape which depends on the cross section of the toroidal core (441, also see Fig. 7.5. Each coil has two active surfaces and each coil surface interacts wit11 the facing PM rotor. In order to achieve the opposite motion of the two rotors, the stator winding coils have to be arranged in such a manner that counter-rotating magnetic fields are produced in the machine's annular air gaps. The stator is positioned between two rotors, which consist of mild steel disks and axially magnetized NdFeB PMs. The magnets are mounted on the disk's surface from the stator sides. Each rotor has its own shaft, which drives a propeller, i.e., the motor has two coaxial shafts which are separated by a radial bearing. The arrangement is shown in Fig. 7.20 [44]. " [Source ~ PMMT p.336]