Attenuation of vibrations due to unbalance of an active magnetic bearings milling electro-spindle

Among the advantages of active magnetic bearings, the absence of contact, the lifetime and the safety can be put forward. This paper presents first a new technology of milling electro-spindle equipped with a permanent magnet motor and active magnetic bearings. Then due to the use of numerical controllers, the implementation of advanced algorithms is easily performed, to ensure a numerical compensation of the rotor unbalance. The aim is to determine the value of the rotor unbalance when classical adaptive compensation methods can't be used for stability reasons. Finally, by reducing the synchronous vibration due to the rotor eccentricity without destabilizing the system, a better resulting surface of the workpiece is expected while avoiding amplifiers saturation.