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Smart Structures and Systems
  Volume 9, Number 4, April 2012 , pages 303-311

Investigations on critical speed suppressing by using electromagnetic actuators
Jarir Mahfoud and Johan Der Hagopian

    The possibility of suppressing critical speeds by using electromagnetic actuators (EMAs) is assessed experimentally in this paper. The system studied is composed of a horizontal flexible shaft supported by two ball bearings at one end and one roller bearing that is located in a squirrel cage at the other end. Four identical EMAs supplied with constant current are utilized. The EMAs associated to the squirrel cage constitutes the hybrid bearing. Results obtained, show that the constant current, when applied to the EMAs, produces a shift of the first critical speed toward lower values. Moreover, the application of constant current for a speed interval around the critical speed enables a smooth run-up or run-down without crossing any resonance.
Key Words
    critical speeds; electromagnetic actuators; rotordynamics; hybrid bearings; experiments
Jarir Mahfoud and Johan Der Hagopian : Universite de Lyon - Laboratoire de Mecanique des Contacts et des Structures - UMR CNRS 5259, Institut National des Sciences Appliquees de Lyon, France

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