Electromechanical Vibration in the Radiation Shield of a Turbogenerator with a Superconducting Field Winding

For thermal insulation, a superconducting turborotor must have a radiation shield. This is a thin-walled flexible cylinder (shell). This paper describes a theory of the vibration behavior of such a shell, including the interaction between the electromagnetic and mechanical phenomena. This theory confirms that the pure "mechanical" resonance frequencey is somewhat increased to an "electromechanical" value, and shows that at the mechanical resonance the eddy currents, and therefore the electrical shielding effect of the radiation shield, disappear. The amplitudes of the shield vibration deflections remain finite, even at electromechanical resonance. Because of the influence of the additional electrical shield used in the larger machines, the maximum deflections are practically negligible.