Active Balancing of a Flexible Rotor in Active Magnetic Bearings

Vibrations mostly caused by mass-unbalance reduce the reliability, the operational safety and the life cycle of high speed rotors. This leads to costly outages and un-scheduled maintenances. Commonly used offline bal-ancing processes are very expensive for the machine user. To reduce these costs and to realize an uninter-rupted control of the balancing states during operation, a complete automatic balancing strategy is proposed. It is based on the combination of the active magnetic bear-ings, the active balancing devices, and the drive motor and is applied to a flexible low pressure shaft of a heli-copter engine test rig. Experimental results validate the efficiency of the proposed strategy.