1. Rotors and unbalances

1.1 Rotors

• A rotor consists of a shaft on which the active parts (wheels, windings, gears, etc.) are mounted. It is held in the stator by rotating connections (radial bearings and an axial thrust bearing); the journals are the parts of the shaft facing the bearings. A cantilever coupling transmits the drive torque.

  Figures 1 (schematic diagram of an electrical machine) and 2 (alternator rotor) show inter-bearing rotors with the active part located between the trunnions. Figures