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| Nonlinear vibration analysis of an eccentric rotor with unbalance magnetic pull |
| SONG Zhiqiang1,2; MA Zhenyue1 |
| (1.School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116023, China; 2.Faculty of Water Resources and Hydraulic Power, Xi’an University of Technology, Xi’an 710048, China) |
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Abstract The unbalance magnetic pull on the rotor of an eccentric water turbine generator set has important influence on its vibration. The magnetic stiffness matrix was introduced to express the energy of the in magnetic gield air gap. Two vibration models were constructed, making use of Lagrange equation. The difference between the two models lies in the boundary supporting conditions: one is rigidly supported and the other is with elastic bearing supports. The influences of magnetic stiffness and elastic supports on the critical speed of rotor were studied using Liapunov nonlinear vibration theory. The vibration amplitude of the rotor was calculated, taking the magnetic stiffness and eccentrical force into account. The sensitivities of the magnetic, mechanical and bearing parameters to with respect the critical speed were analyzed. Some conclusions may be benefit to the study of dynamic characters of the generator set shaft system which concludes all the magnetic, mechanical and hydraulic parameters.
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Received: 26 May 2009
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2010, Vol. 29 
