The effect of surge testing on the voltage endurance life of stator coils
Bibliographic record
Abstract
Surge tests with short rise times are used to ensure turn insulation integrity in dry vacuum-pressure impregnated (VPI) coils. The use of this test migrated from the evaluation of low voltage random wound stators and fully processed generator bars. The dielectric properties of dry (unimpregnated) VPI coils are not fully developed. Application of a high voltage transient electric field in uncured or partially processed coils may initiate insulation damage. This damage may shorten the life of the insulation system after complete impregnation and cure. This paper presents a series of laboratory tests and finite element simulations examining the applied test voltage and number of applied pulses as factors in determining the risk of using surges as a manufacturing proof test on unimpregnated coils. Potential failure initiation sites can be linked to the test voltage as a more significant factor than the number of pulses applied. The sympathetic voltage response in a single coil as a function of location within a winding is described for a 20-pole stator undergoing green surge testing as part of a quality assurance program. Voltage endurance testing and sample dissection data are presented to show that the voltage endurance test life of the coils after complete processing is shortened by the surge test.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".