IS/IEC 61558-2-4 : 2021 Safety of Transformers, Reactors, Power Supply Units and Combinations Thereof - Part 2 Particular Requirements and Tests for Safety Isolating Transformers and Power Supply Units Incorporating - Section 4 Isolating Transformers for General Applications
NATIONAL FOREWORD
This Indian Standard (Part 2/Sec 4) (First Revision) which is identical to IEC 61558-2-4 : 2021 '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' issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the Transformers Sectional Committee and approval of the Electrotechnical Division Council.
This standard was first published in the year 2019. This revision has been taken up to align with the latest IEC standard. The major changes from the previous version are:
a) Adjustment of structure and references in accordance with IS/IEC 61558-1 : 2017 (under preparation);
b) Description of constructions moved to IS/IEC 61558-1 : 2017 (under preparation); and
c) A new symbol for power supply unit with linearly regulated output voltage.
The text of the IEC standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:
a) Wherever the words 'International Standard' appears referring to this standard, they should be read as 'Indian Standard'; and
b) Comma (,) has been used as a decimal marker, while in Indian Standards the current practice is to use a point (.) as the decimal marker.