Comparative AC and DC voltage endurance tests performed on Roebel bars
Bibliographic record
Abstract
Measurement of the charging and discharging current of stator winding insulation under DC high voltage is one of the tests used in the condition assessment of rotating machines. Since the high voltage may be applied for a relatively long period of time during the charging of the winding, its value can be a matter of concern. No aging of the insulation under test should occur while the condition assessment is performed. In order to be able to compare the aging effect of AC and DC high voltage on the groundwall insulation of a stator winding, the so-called Voltage Endurance Test (VET) was performed on 12 spare 13.8-kV Roebel bars. Half the test specimens were subjected to a voltage of 35 kVac; for this test, a ratio of 1.7 between direct voltage and power frequency voltage (rms) was used. The other half were then tested at a voltage of 59.5 kVdc. This paper presents the results of this comparative VET between AC and DC voltages performed on epoxy-mica based insulation of hydro-generator Roebel bars.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.003 | 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".