Vibration Study and Classification of Rotor Faults in PM Synchronous Motor

Both radial and axial direction Repeatable Run-Out (RRO) and none repeatable Run-Out (NRRO) of spindle motor in HDD is a big concern in high TPI requirement. Besides the reasonable spindle motor structure design which studied in [3]–[4], the fabrication tolerance of spindle motor parts should be controlled in order to minimum RRO and NRRO. As it is known, the vibration of spindle motor is mainly caused by unreasonable Unbalance Magnet Pull (UMP). Different motor parts faults (tolerance is out of the control) will generate different types of UMP which should be generate different vibration signals pattern. Though studying different vibration signals and acoustic noise pattern, the types of UMP or other faults should be detected and classified. then, the related out of tolerance controlled parts can be known. Researchers have studied vibration and acoustic signals in recent years [5][6]–[7]. In this paper, the 12 slots and 5 pole-pairs PM surface mounting Synchronous motor is modified as M₁ to do experimental study. This paper can be a guideline of design high performance motor; it also can be the reference of general motor fault diagnosis.