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Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

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“Invent a New India Using Knowledge”

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“Step Out From the Old to the New”

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“The Right to Information, The Right to Live”

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“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 10242-3-3 (1984): Electrical installations in ships,Part 3: Equipment, Section 3: Transformers for power andlighting [ETD 20: Electrical Installation]

IS : 10242 ( Part 3/Set 3 ) - 1984

Indian Standard SPECIFlCATION FOR

ELECTRICAL INSTALLATIONS IN SHIPS

PART 3 EQUIPMENT

Section 3 Transformers for Power and Lighting

Electrical Equipment and Installations in Ships Sectional Committee, ETDC 62

Chairman Representing

SI~I~I H. K. TANEJA Indian Register of Shipping, Bombay

Members

SHRI’S. C~AKDRA ( Alternate to Shri H. K. Taneja )

S~RIA.N. ACARWAL Central Scientific Instruments Organization ( CSIR ), Chandigarh

SHRI V. K. SEHG~L ( Alternate ) SHRI S. S. ANAND Directorate of Warships Projects, New Delhi

SHRI M. P. SIN~R ( Alternate ) f&RI c. R. BALASuRHA~rA~IAN The English Electric Co of India Ltd, Madras

SHRI K. VASUUEVAN ( Alternate ) SKRI S. N. BASS1 Garden Reach Shipbuilders & Engineers Ltd,

Calcutta SHRI A. D. BI-IATTACHI~YA ( Akernate )

CUR A. M. BHOOPATI Directorate of Standardization, Department of Electrical Engineering ( Ministry of Defencc )

CDR M. S. C~IANDRASHEGI*AR ( Alternate ) &RI N. CHAI<RABORTY Directorate General of Shipping, Bombay

SHRI B. 33. B~uw.4~ ( Alternate ) DIE L. R. CHABY The Shipping Corporation of India Ltd, Bombay

SHRT N. N. BaHADtJRI ( Akernate ) Smr S. P. CHAUDHRY Delton Cable Industries Ltd, New Delhi

SHUI P. MUKU,Y>AN ( Alternate ) SWRI U. J. D’SILVA Scindia Steam Navigation Co Ltd, Bombay

Sunr J. MANSU~HANI ( Alternate ) SIIRI S. K. DATTA General Electric Co of India Ltd, Calcutta SHI+I A. N, GHOST Development Commissioner, Small Scale Industries,

New Delhi SIfRI A. BANDYOPADHYAY ( Alternate )

( ContinuGd on page 2 )

@ Copyright 1985

INDIAN STANDARDS INSTITUTION

This publication is protected under the Indian Copyright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the nublisher shall be deemed to be an infringement of copyright under the said Act.

IS : 10242 ( Part 3/Set 3 ) - 1984

( Continued from page 1 )

Members Representing

SHRI L. GOPALAKRISHNAN Directorate General of Technical Development, New Delhi

CI)R HARDTAL SIN~II Directorate of Production Inspection ( Naval ) ( DGI ), Ministry of Defence

Con VIN~D KTJMAR ( Alternate ) SHRI K. KISllORE Directorate of Marine Engineering Training,

Bombay SNRI D. K. SANYAL ( ,&rnUte )

SHRIM.M.oKA Crompton Greaves Ltd, Bombay SHRI M. G. BHAT ( Alternate )

SKRI K. V. MANJUNA~IX Kirloskar Electric Co Ltd, Bangalore SHRI N. RAYACHANDRA ( Alternote )

SHRI P. V. NARASIMHAN Hindustan Shipyard Ltd, Vishakhapatnam SRRI P. S. P. RAO ( Alternate)

SHRI H. D. PENDSE Mazagon Dock Ltd, Bombay SHRI W. R. PATWARDHAN ( Alternate )

SHRI V. MOHAN Larsen & Toubro Ltd, Bombay SHRI A. M. MUNSIII ( Alternate )

SHRI M. A. NOORUDDIN Siemens India Ltd, Bombay SRRI R. JAIRAM ( Alternate )

DR B. RAQHUNATH Jyoti Ltd, Vadodara SHRI R. PALANI ( Alternate )

SHRI K. R. RAMACHANDRAN Bharat Heavy Electricals Ltd, Hyderabad SHRI S. C. BH~ROAVA ( Alternate 1 ) SHRI V. R. GARDE ( Alternate II )

SERI K. V. R. RAO The Indian Cable Co Ltd, Jamshedpur SHRI S. BHAT~ACRARYA ( Alternate )

SERI K. P. SARATHY NGEF Ltd, Bangalore SHRI JAVEED AHMED ( Alternate )

SHRI P. J. C. SERENO Cochin Shipyard Ltd, Cochin Snnr A. K. MUKHERJ~E ( Alternate )

SARI S. P. SACHDEV, Director General, IS1 ( Ex-o&o Member ) Director ( Elec tech )

Secretary

SHRI SUKH BIRSINQH Deputy Director ( Elec tech ), IS1

Panel for Generators, Motors and Transformers, ETDC 62/P2

Convener

Snnr K. V. MANJUNATH

Members

Kirloskar Electric Co Ltd, Bangalore

SHRI N. RANACHANDRA ( Alternate to Shri K. V. Manjunath )

SHRI S. N. BASSI Garden Reach Shipbuilders & Engineers Ltd, Calcutta

SHRI A. D. BHATTACHARYA ( Ahernate )

( Continued on page 8 )

2

IS :10242(Part3/Sec 3)-1984

Indian Standard SPECIFICATION FOR

ELECTRICAL INSTALLATIONS IN SHIPS

PART 3 EQUIPMENT

Section 3 Transformers for Power and Lighting

0. FOREWORD

0.1 This Indian Standard ( Part 3/See 3 ) was adopted by the Indian Standards Institution on 14 November 1984, after the draft finaljzed by

the Electrical Equipment and Installations in Ships Sectional Committee had been approved by the Electrotechnical Division Council.

0.2 This standard is one among the series of Indian Standards for electrical installations in sea-going ships incorporating good practices and coordinating as far as possible existing rules. This standard along with its other parts provides a code for practical interpretation and amplifica- tion of the requirements of the ‘International convention on safety of life at sea’, a guide for future regulations which may be prepared and a statement of practice for use by ship-owners, ship-builders and appro- priate organizations.

0.3 This series of Indian Standards on electrical installations in ships consists of the following parts:

Part 1 General

Part 2 System design

Part 3 Equipment

Part 4 Installation and test of completed installation

Part 5 Special features

0.3.2 Under Part 3 different sections have been prepared to deal with individual equipment. Other sections which have already been published are as follows:

Set 1 Generators and motors

Set 2 Switchgear and controlgear assemblies

3

.

IS : 10242 ( Part 3/Set 3 ) - 1984

0.4 In the preparation of this standard assistance has been taken from IEC Pub 92-363 ( 1980 ) ‘Electric installations in ships: Part 303 Equip- ment - Transformers for power and lighting’, issued by the International EIectrotechnical Commission ( IEC ).

0.5 This part of the standard shall be read in conjunction with the other appropriate parts mentioned in 0.3.

0.6 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accord- ance with IS 2-1960*. ‘The of significant places in the rounded value should the same that of specified value in

standard.

1. SCOPE

1.1 This standard ( Part 3/Set 3 ) is applicable to all transformers used for power, lighting and static convertors and where appropriate to starting transformers, static balancers, saturable reactors and transductors for use in ships, including single-phase transformers rated at less than 1 kVA, and three-phase transformers rated at less than 5 kVA, unless special requirements are specified.

2. GENERAL REQUIREMENTS

2.1 All equipment referred to in the scope shall comply with the relevant requirements of the standards referred to hereinafter as we11 as with the additional requirements given in this standard and in other parts of this standard as far as applicable:

IS : 2026 ( Part 1 )-1977 Power transformers: Part 1 General ($fivsb rtWisio?t )

IS : 2026 ( Part 2 )-1977 Power transformers: Part 2 Temperature rise ( jirst revision )

IS : 2026 ( Part 3 )-1981 Power transformers: Part 3 Insulation levels and dielectric test ( second revision )

IS : 2026 ( Part 4 )-I977 Power transformers: Part 4 Terminals marking, tappings and connections ( jirst revision )

IS : 2511-1963 Polycrystalline semiconductor rectifier stacks

IS : 3136-1965 Polycrystalline semiconductor rectifier equipment

IS : 3895-1966 Monocrystalline semiconductor rectifier cells and stacks

-~ ~~.__~ .- *Rules for rounding off numerical values ( revised ).

4

IS : 10242 ( Part 3/Set 3 ) - 1984

1s : 4540-1968 Monocrystalline semiconductor rectifier assemblies and equipment

IS : 8544 ( Part 4 )-1979 Motors starters for voltages not exceeding 1 000 V: Part 4 Reduced voltage ac starters: two step auto transformer starters

3. WINDING ARRANGEMENT

3.1 Transformers shall be double-wound ( two separate windings ). Starting transformers may be of the auto-transformer type.

3.2 All windings of aircooled transformers are to be treated to resist moisture, sea air and oil vapours.

4. TERMINALS

4.1 Suitable terminals, clearly marked, shall be provided in an accessible position, convenient for external connections. The terminals shall be effectively secured and shall be SO spaced and/or shielded that they cannot be accidentally earthed, short-circuited or touched.

5. COOLING ARRANGEMENTS

5.1 Transformers shall preferably be of dry, natural air-cooled type.

5.2 Transformers of the liquid-immersed type shall preferably be herme- tically sealed. If of the conservator type, they shall be so designed that under all conditions of operation with the ship inclined from the normal as specified in Part l/Set I* of this standard they operate without risk of spilling liquid., If provision is made for breathing, a suitable dehydrator shall be provided.

5.2.1 The cooling liquid shall not be spilled when the transformer is inclined 40” from the normal.

5.2.2 Drip trays or other suitable provisions for collecting the liquid by leakages shall be arranged. A liquid gauge indicating the normal liquid level range shall be fitted.

5.3 For liquid-immersed type transformers, consideration shall be given to provide liquid over-temperature alarm and gas-actuated protection devices.

NOTE - See Part 4 of this standard which covers installation and test of completed installation, regarding installation precautions ( undrtfire#arution ).

*Electrical installations in ships: Part 1 General, Section 1 Definitions and general requirements.

5

IS : 10242 ( Part 3jSec 3 ) - 1984

6. VOLTAGE REGULATION

6.1 The voltage drop in the secondary voltage between no load and rated load, under resistive load, shall not exceed 5 percent for transformers rated up to 5 kVA per phase and 2’5 percent for transformers rated at more than 5 kVA per phase, except that for starting transformers the voltage shall be subject to agreement between the manufacturer and the purchaser.

NOTE 1 - When determining the transformer ratio and the short-circuit impedance, consideration shall be given to total voltage drop to be expected in the supply and distribution system. In this respect reference is also made to Part ?/Set I* of this standard.

NOTE 2 -This clause contains requirements that have to be agreed between the manufacturer and the purchaser.

6.2 Transformer should be constructed to withstand secondary terminal short-circuits during one second with rated primary voltage and frequency without damage. This may be required to be verified by type test or random test.

7. PARALLEL OPERATION

7.1 When transformers are so arranged that their secondary windings may be connected in parallel, their winding connections shall be com- patible, their rated voltages ratios shall be equal ( with tolerances allowed ) and their short-circuit impedance values, expressed in percent- age, shall have a ratio within 09 to I* 1. When transformers are intended for operation in parallel, the rated power of the smallest transformer in the group shall be not less than half of the rated power of the largest transformer in the group.

7.2 During the parallel operation the actual current of each transformer shall not differ from its proportionate share of the total load by more than 10 percent of its full load current.

8. TEMPERATURE-RISE LIMITS

8.1 Temperature-rise limits shall be defined in accordance with IS : 2026 ( Part 2 )-1977t taking into consideration the ambient temperature referred to in Part l/Sac l$ of this standard.

8.2 Additional requirements for liquid cooled transformers shall be as follows:

a) Maximum temperature-rise for windings 55%; and

*Electrical installations in ships: Part 2 System design, Section 1 General. *Specification for power transformers: Part 2 Temperature-rise. fElectrica1 installations in ships: Part 1 General, Section 1 Definitions and general

requirements.

6

IS : 10242 ( Part J/Set 3 ) - 1984

b) Maximum temperature-rise for liquid, when the liquid in the main tank is protected from contact with air 50°C. If the above is not the case 45°C.

9. TESTS

9.1 All the type and routine tests given in the relevant Indian Standards shall apply.

9.2 If a short-circuit test is required to prove the short-circuit ability of a transformer, it shall be a type test and shall be in compliance with IS : 2026 ( Part 1 )-1977*.

9.3 All transformers shall be capable of withstanding without damage the thermal and mechanical effects of a short-circuit at the terminals of any winding for 2 seconds.

*Specification for power transformers: Part 1 General (first revision ).

7

IS : 10242 ( Part 3/Set 3 ) - 1984

( Continuedfrom page 2 )

Members Representing

DR L. R. CHAXP The Shipping Corporation of India Ltd, Bombay SRRI N. N. BAHA~UIU ( Alternate )

CUR HARDYAL SINCH Directorate of Production Inspection ( Naval ) ( DGI ), Ministry of Defence

CDR VINOD KUMAR ( Alternate ) SEIRI P. V. NARASIMHAN Hindustan Shipping Ltcl, Vishakhapatnam

SHRI P. S. RAO ( Alternate ) SRRI M. A. NOORUDDIN Siemens India Ltd, Bombay

SHRI R. JAIRAM ( Alternate) SRRI M. M. OKA Crompton Greaves Ltd, Bombay

SRRI M. G. BOAT ( Alternate ) SHRI H. D. PEXDSE Mazagon Dock Ltd, Bombay

SHRI W. R. PATWARDHAN ( Alternate ) DR B. RAQHUNATH Jyoti Ltd, Vadodara

SHRI R. PALANI ( Alternate ) SHRI K. P. SARATHY NGEF Ltd, BangaIore

SRRI JAVEED AHMED ( Alternate )

8