Measurement of vibrations and radiated acoustic noise of electrical machines
Bibliographic record
Abstract
The investigations reported in this paper mainly concern the vibration and noise aspects of polyphase induction motors. Although the investigations are focused on induction machines, the fundamental results presented in the paper will be applicable to other types of rotating electrical machines. The maximum allowable noise levels associated with the operation of electrical machines of different sizes and speeds are stipulated in the various standards. Although these noise levels represent the upper limits, they do not necessarily reflect upon the achievable levels with the present state of art in the design of electrical machines. Considering the physiological characteristics of the human ear, magnetic noise of electrical machines is particularly troublesome since it is characterised by many pure tones. The conventional methods for the measurement of resonant frequencies, vibrations and noise are laborious and very time consuming. This paper presents the laboratory-techniques which have been developed for the measurement of resonant frequencies, vibrations and noise based on digital processing of signals. The measurement set-up acquires and processes signals from several transducers with the help of a data-acquisition system and a personal-computer.
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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 | 0.000 |
| 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".