BS EN IEC 61788-24:2018
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Superconductivity – Critical current measurement. Retained critical current after double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires
| Published By | Publication Date | Number of Pages |
| BSI | 2018 | 36 |
IEC 61788-24:2018 describes a test method for determining the retained critical current after double bending at room temperature of short and straight Ag- and/or Ag alloy-sheathed Bi-2223 superconducting wires that have the shape of a flat or square tape containing mono- or multicores of oxides. The wires can be laminated with copper alloy, stainless steel or Ni alloy tapes. The test method is intended for use with superconductors that have a critical current less than 300 A and an n-value larger than 5.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 7 | English CONTENTS |
| 9 | FOREWORD |
| 11 | INTRODUCTION |
| 12 | 1 Scope 2 Normative references 3 Terms and definitions |
| 13 | 4 Principle 5 Apparatus 5.1 General 5.2 Bending mandrel 5.3 Critical current measurement holder |
| 14 | 5.4 Critical current measuring system 6 Specimen preparation and set up 6.1 Length of specimen Figures Figure 1 – Sample holder |
| 15 | 6.2 Mounting of the specimen 7 Measurement procedures 7.1 Critical current measurement 7.2 Double bending |
| 16 | 7.3 Retained critical current after bending 8 Calculation of results 8.1 Critical current criteria 8.2 n-value (optional) 9 Test report 9.1 Identification of test specimen |
| 17 | 9.2 Report of Ic values and/or retained Ic ratio 9.3 Report of Ic test conditions Figure 2 – Intrinsic U-I characteristic Figure 3 – U-I characteristic with a current transfer component |
| 18 | Annex A (informative)Additional information relating to Clauses 1 to 9 A.1 General A.2 Measurement condition A.3 Apparatus measurement holder material |
| 19 | Tables Table A.1 – Thermal expansion data of Bi-2223 superconductors and selected materials |
| 20 | Figure A.1 – Measurement configuration for a few hundred ampere class conductor Figure A.2 – Clips |
| 21 | A.4 Specimen preparation A.5 Measurement procedures A.5.1 Critical current measurement Figure A.3 – Additional strain caused by voltage tap wires and solders |
| 22 | Figure A.4 – Boiling temperature of liquid nitrogen versus atmospheric pressure |
| 23 | A.5.2 Bending Figure A.5 – Critical current versus temperature for a typical Bi-2223 wire |
| 24 | A.6 Calculation of results A.6.1 Critical current criteria A.6.2 n-value Figure A.6 – Bending process |
| 25 | A.7 Relative standard uncertainty |
| 26 | Table A.2 – Average of the degree of retained critical current (Ic/Ic0),their relative standard uncertainty and coefficient of variance |
| 27 | Annex B (informative)Evaluation of combined standard uncertainty for the retained Ic after double bending B.1 Practice of critical current measurement B.2 Model equation Figure B.1 – U-I diagram Table B.1 – Precondition for evaluating standard uncertainty |
| 28 | B.3 Operation for the retained Ic measurement B.4 Combined standard uncertainty |
| 29 | B.5 Evaluation of standard uncertainty (SU) for each measurand B.5.1 Voltage tap length (L) B.5.2 Voltage (U) |
| 30 | B.5.3 Current (I) |
| 31 | B.6 Evaluation of combined standard uncertainty Table B.2 – Partial sum (Equation (B.17) of standard uncertainty as related to the current measurement) |
| 32 | Table B.3 – Budget table of standard uncertainty for each component Table B.4 – Combined standard uncertainty |
| 33 | Figure B.2 – Bending diameter dependence of the retained Ic and , where the calculated curve of Ic/Ic0 gives Equation (B.24) |
| 34 | Bibliography |
