Dynamic characteristics of low loss motorized spindle suspended by magnetic bearings

A low loss motorized spindle suspended by magnetic bearings with two radial homopolar active magnetic bearings(AMB)and one axial permanent magnetic bearing(PMB)was established,and the main design procedure and configuration parameters of the system were presented.The dynamic characteristics of the system were analyzed by theoretical calculations and verified by high-speed rotation tests.The results show that the system has simpler structure,less power consumption,and is able to get across the first two critical speeds and operate at 40 000r/min safely,with maximum amplitude of the rotor up to 7μm.