ABSTRACT
The restoring force is directly related to the motor friction torque which is a key factor during diagnosing the motor bearing fault based on Motor Current Signature Analysis (MCSA), but the restoring force characteristic has not yet been fully revealed when the region of bearing fault defect gradually enlarges. Based on the dynamic model, the restoring force is calculated in this thesis. The result shows a very important feature that along with the enlargement of the bearing defect zone, the pulse width of restoring force curve is expanded. The present conclusion that differs from traditional ideal assumption, is significative for motor bearing fault diagnosis based on MCSA.
