A Problematic Field Experience Using Surge Testing

Surge testing of stator windings has long been used as part of incoming testing for inspections and documentation for machines with periodic maintenance plans. While IEEE 522 and IEC 60034–15 offer some guidance for performing the test on windings and windings which have been aged, neither offers acceptable results when comparing resulting wave forms from different phases or technical explanations to problems. It is known steep front rise time surge comparisons only applies electrical stress the first few turns of the first coil or coils in a phase and may not be useful in checking the dielectric performance past the first coil. This paper will explain an experience which surge comparison was used as part of an incoming test plan, the questionable comparison results, the issue, remediation, corrected results, and a proposal for suggested acceptable separation of resulting waveform between phases