BS 6647:1985 BRITISH STANDARD IEC 790:1984 Guide to Oscilloscopes and peak voltmeters for impulse tests UDC [621.317.726 + 621.317.75].004.15 BSi BS 6647:1985 Committees responsible for this British Standard BSI The preparation of this British Standard was entrusted by the Power Electrical Engineering Standards Committee (PEL/-) to Technical Committee PEL/62 upon which the following bodies were represented: Association of Short Circuit Testing Authorities British Industrial Ceramic Manufacturers' Association Electric Cable Makers Confederation Electrical and Electronic Insulation Association (BEAMA Ltd.) Electricity Supply Industry in England and Wales Transmission and Distribution Association (BEAMA Ltd.) This British Standard, having been prepared under the direction of the Power Electrical Engineering Copy: Standards Committee, was published under the authority of the Board of BSI and comes into effect on Amendments issued since publication nsed 31October1985 Date of issue Amd. No. Comments Licen CBSI 09-1999 The following BSI references relate to the work on this standard: Committee reference PEL/62 Draft for comment 79/23238 DC ISBN 0 580 14663 4 BS 6647:1985 Contents Page Committees responsible Inside front cover BSI National foreword ii Section 1. General 1 Scope 1 2 Object 1 3 Conditions of use 1 3.1 Range of operating conditions 1 3.2 Reference conditions 2 4 General definitions 2 4.1 Transfer characteristic 2 4.2 Scale factor 2 Deflection coefficients 2 4.3 4.4 Nominal values of the deflection coefficients 2 Non-linearity 2 4.5 4.6 Instability 2 4.7 Measuring area or scale 2 4.8 Rated deflection or rated scale 2 4.9 Effective screen areas or effective scale 2 Warm-up time 4.10 3 Absolute and relative error 3 4.11 Individual error and overall error 3 4.12 5 Performance characteristics 3 6 Input characteristics 3 Section 2. Oscilloscopes for impulse tests 7 General 3 7.1 Writing speed 4 7.2 Step response and rise time 4 7.3 Oscilloscope frequency response 4 8 Accuracy requirements 4 8.1 General 4 8.2 Requirements on transfer characteristics 4 8.3 Requirements on the accuracy of the calibration 4 8.4 Requirements on linearity 5 8.5 Requirements on stability 5 8.6 Requirements on ripple 5 8.7 Requirements on the accuracy of the reading process 8.8 Limits on interference 5 9 Record of performance 5 10 Recommended procedure for oscilloscope measurements 6 Section 3. Peak voltmeters for impulse tests 11 General 6 12 Accuracy requirements 6 12.1 6 General Requirements on transfer characteristics 7 12.2 Requirements on accuracy of the calibrators 7 12.3 Requirements on linearity 12.4 12.5 Requirements on stability 7 12.6 Requirements on storage time 7 CBSI 09-1999 1