1、 IEC 61558-2-4 Edition 3.0 2021-05 INTERNATIONAL STANDARD Safety of transformers,reactors,power supply units and combinations thereof Part 2-4:Particular requirements and tests for isolating transformers and power supply units incorporating isolating transformers for general applications IEC 61558-2
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9、aining more than 22 000 terminological entries in English and French,with equivalent terms in 18 additional languages.Also known as the International Electrotechnical Vocabulary(IEV)online.INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 29.180 IEC 61558-2-4 ISBN 978-2-8322-9790-2 GROUP SAFETY PUBLICAT
10、ION Edition 3.0 2021-05 Registered trademark of the International Electrotechnical Commission INTERNATIONAL STANDARD Warning!Make sure that you obtained this publication from an authorized distributor.Safety of transformers,reactors,power supply units and combinations thereof Part 2-4:Particular req
11、uirements and tests for isolating transformers and power supply units incorporating isolating transformers for general applications 2 IEC 61558-2-4:2021 IEC 2021 CONTENTS FOREWORD.3 INTRODUCTION.6 1 Scope.7 2 Normative references.8 3 Terms and definitions.8 4 General requirements.8 5 General notes o
12、n tests.8 6 Ratings.9 7 Classification.9 8 Marking and other information.9 9 Protection against electric shock.10 10 Change of input voltage setting.10 11 Output voltage and output current under load.10 12 No-load output voltage.10 13 Short-circuit voltage.11 14 Heating.11 15 Short-circuit and overl
13、oad protection.11 16 Mechanical strength.12 17 Protection against harmful ingress of dust,solid objects and moisture.12 18 Insulation resistance,dielectric strength and leakage current.12 19 Construction.12 20 Components.12 21 Internal wiring.12 22 Supply connection and other external flexible cable
14、 or cords.12 23 Terminals for external conductors.12 24 Provisions for protective earthing.12 25 Screws and connections.12 26 Creepage distances,clearances and distances through insulation.12 27 Resistance to heat,fire and tracking.12 28 Resistance to rusting.13 Annexes.14 Bibliography.15 Table 101
15、Symbols indicating the kind of transformer.10 Table 102 Output voltage ratio.11 IEC 61558-2-4:2021 IEC 2021 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ SAFETY OF TRANSFORMERS,REACTORS,POWER SUPPLY UNITS AND COMBINATIONS THEREOF Part 2-4:Particular requirements and tests for isolating transformers
16、and power supply units incorporating isolating transformers for general applications FOREWORD 1)The International Electrotechnical Commission(IEC)is a worldwide organization for standardization comprising all national electrotechnical committees(IEC National Committees).The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields.To this end and in addition to other activities,IEC publishes International Standards,
