A New Algorithm of Online Stator Faults Diagnosis of Three-Phase Induction Motors Using Duty Ratios of Half-Period Frequencies According to Phase Angle Changes

The causes of faults of induction motors are largely categorized into bearing fault, which causes a mechanical fault, and stator fault and rotor fault, which cause an electrical fault. A stator fault among these faults, which causes an electrical fault, occurs due to the breakdown of insulation, meaning the stator is directly connected with the power supply, and the direct connection is a direct cause of a major accident. For this reason, many studies are being performed to detect the faults. This paper explained the effects of a negative sequence on phase angle change by analyzing the effects of the existing negative sequence on the d-q transform of Park's vector approach. This paper suggested a new algorithm that identifies the causes of stator faults with the use of the change in the duty ratio of the half-period frequency of the frequency when a phase angle change occurs at that moment.