Multiple-Fault Detection Methodology Based on Vibration and Current Analysis Applied to Bearings in Induction Motors and Gearboxes on the Kinematic Chain

Figure 9

PSD spectrum from current signal when VFD is set to 15 Hz.

(a) For the healthy condition and all wear levels

(b) For the healthy condition, bearing defect, 75% of uniform wear, and 75% of uniform wear + bearing defect