Vibration Diagnosis of Fan Motor Excited by Swing Motion

Abstract

The small fan motors are used by many electronics for cooling device. They are essential for present industry. However, quality inspection of the small fan motor is conducted an organoleptic test by inspectors who have special skills which are based upon their auditory organs and tactual senses. It is not easy that inspectors will have mastered those skills. In addition, there is a problem of those skills sometimes depend upon their mental and physical condition. Therefore, quality assurance is considered insufficient. When we observed inspectors to perform organoleptic test of the small fan in the actual production line, organoleptic inspector diagnosed rotation sound and vibration of the small fan to turn the wrist and to close the ear in the state of holding the small fan. Then we considered an operation to excite a vibration to the small fan to add unsteady displacement. Therefore, The study measured the vibration acceleration signal of the small fan by equipment imitating the handling operation performed by the inspectors and aimed at realizing quality diagnosis by Mahalanobis’ Distance (below “MD”) from average value of measured vibration (Time average value of the RMS level of the vibration acceleration signal ) and its deviation (the difference between the maximum value and minimum value of the vibration acceleration level ).