Influence of the Location of a Bearing Fault in Induction Motor Multi-Sensor Diagnostics

A new multi-sensor investigation aimed at evaluating the influence of the bearing fault location in induction motor diagnostics is presented in this paper. Experimental tests were carried out on a machine with a cracked bearing, where the angular position of the crack was varied with respect to the load zone. The machine has been tested at no-load, at constant load and with low frequency torque oscillation. Five signals were measured: vibration with two different accelerometers in two different positions, stator current and external stray flux along radial and axial direction with two different sensors. Comparisons between these signals from the healthy motor and the same motor with the cracked bearing in different positions are used to determine the diagnostic efficiency of the system. Moreover, new diagnostic insights are pointed out, coming from a comparison between the two vibration signals in different loading conditions.