Experimental Observation of Vertical Flexible Shaft Generation Roll over a Rigid Stator

The frequency responses of four experimental shafts in a generation roll over a comparatively stiff stator are presented. The initial conditions of existence and stability of the generation roll in the isotropic rotor–stator system are empirically determined. These conditions are reduced to rotation with a rotation speed near the first eigenfrequency on bearings and to friction with a sliding friction coefficient of 0.1 and higher in the place of contact between the rotor and stator. The upper boundary of the generation roll stability in the rotation speed is not discovered.