BS EN 61251:2016
$142.49
Electrical insulating materials and systems. A.C. voltage endurance evaluation
| Published By | Publication Date | Number of Pages |
| BSI | 2016 | 26 |
This International Standard describes many of the factors involved in voltage endurance tests on electrical insulating materials and systems. It describes the voltage endurance graph, lists test methods illustrating their limitations and gives guidance for evaluating the sinusoidal a.c. voltage endurance of insulating materials and systems from the results of the tests. This International Standard is applicable over the voltage frequency range 20 Hz to 1 000 Hz. The general principles can also be applicable to other voltage shapes, including impulse voltages. The terminology to be used in voltage endurance is defined and explained.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 7 | FOREWORD |
| 9 | INTRODUCTION |
| 10 | 1 Scope 2 Normative references 3 Terms, definitions and symbols 3.1 Terms and definitions |
| 11 | 3.2 Symbols 4 Voltage endurance 4.1 Voltage endurance testing 4.2 Electrical stress |
| 12 | 4.3 Voltage endurance (VE) graph 4.4 Short-time electric strength Figures Figure 1 – General voltage endurance line |
| 13 | 4.5 Voltage endurance coefficient (VEC) 4.6 Differential VEC (nd) 4.7 Electrical threshold stress (Et) Figure 2 – Determination of the differential VEC nd at a generic point P of the VE line |
| 14 | 4.8 Voltage endurance relationship |
| 15 | 5 Test methods 5.1 Introductory remarks 5.2 Tests at constant stress 5.2.1 Conventional VE test |
| 16 | 5.2.2 Diagnostic measurements 5.2.3 Detection of an electrical threshold 5.3 Tests at higher frequency |
| 17 | 5.4 Progressive stress tests |
| 18 | Figure 3 – Plotting the VE line in a progressive stress test using different rates of stress rise |
| 19 | 5.5 Preliminary tests to determine the initial part of the VE line 5.6 Recommended test procedure 6 Evaluation of voltage endurance 6.1 Significance of the VEC |
| 20 | 6.2 Significance of the electrical threshold stress 6.3 Dispersion of data and precision requirements 6.4 Presentation of the results |
| 22 | Annex A (informative) The Weibull distribution A.1 Weibull distribution times to dielectric breakdown A.2 Weibull distribution dielectric breakdown stresses A.3 Generalized Weibull distribution of the dielectric breakdown stresses |
| 23 | A.4 Inverse power model for the time to dielectric breakdown |
| 24 | Bibliography |
