Round cylindrical rotor

Synchronous AC machines have a stator similar to the asynchronous machines, which has usually a three-phase stator winding. Whereas there are two types of rotor structures round cylindrical rotor and salient pole rotor as illustrated schematically in Fig. 5.6. The rotor field is generated by permanent magnets or a DC current winding, as reported in the same figure. In the first case they are called permanent-magnet synchronous AC machines. 

Fig. 5.6 Schematic illustration of synchronous machines of a round or cylindrical rotor and b salient rotor structures...

The rotor of the vane pump is mounted off centre in a cylindrical casing (Figure 8.9). It carries rectangular vanes in a series of slots arranged at intervals round the curved surface of the rotor. The vanes are thrown outwards by centrifugal action and the fluid is carried in the spaces bounded by adjacent vanes, the rotor, and the casing. Most of the wear is on the vanes and these can readily be replaced. 

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