IS:i1287-1985 ( ReaNiu-med 1991)

Indian Standard

( Reaffirmed 1997 )

SPECIFICATION FOR BRIDGE INSULATIONS TESTERS ( MAGNETO GENERATOR TYPE )

. .
( First Reprint MAY 1997 ) -

Y x * me * ., .,. 3 ., .

UDC

621317733

Copyright

1985

1JlJREAU OF INDIAN STANDARDS MANAK Bl-IAVAN, 9 BAI-IADUR SHAH ZAFAR MARC;

NEW DELHI 110002

Gr 4

December

1985

IS:11287 - 1985 (Reaffied 1991)

Indian Standard
SPECIFICkTION FOR BRIDGE INSULATIONS TESTERS ( MAGNETO GENERATOR TYPE )
Electrical Measuring Instruments
PROF

Sectional

Committee,

ETDC

48

Chairman J. K. CHOUDXSURY Jadavpur University, Calcutta Rcprescnting Members The Calcutta Electric Supply Corporation ( I ) Ltd, Calcutta SHRI S. B. MUKHOPADHYAY ( Alternate) SHRI A. K. BASAK Develoument Commissioner. Small Scale Industries ( Ministry of Industry j, New Delhi SHRI A. N. SAHAI ( Alternate ) SHRI V. K. BATRA National Physical Laboratory ( CSIR ), New Delhi SHRI K. P. BHATN_~~AR Directorate of Standardization. Ministrv of Defence ( R & D Organization ), Mew Delhi SHRI B. M. SHAN~AR PRASA~ ( Alternate ) SIIRI J. K. COLACO Larson & Toubro Ltd, Bombay SHIU J. J. DARUWALA All India Instruments Manufacturers & Dealers Association, Bombay SERI P. C. GOLIYA ( Alternate ) SHRI B. P. G~OSH National Test House, Calcutta SHRI B. MUKHOP.~DHY~YA ( Alternate ) SHRI NARENDRA GOLIYA Shanti Electric Instruments, Bombay SHRI H. S. SAWAREAR ( Alternate ) Institute for Designs of Electrical Measuiing SHRI K. V. GOPALAUATNA~~ Instruments, Bombay SHRI B. V. VARDARAJAN ( Altcsnatc ) STANDMWS Research Design & Standards Organization, Ministry JOINT DIRECTOR of Railways, Lucknow ( ELECTRICAL )-6 ASSISTANT DESIGN ENGINEER ( ELECTRICAL )-Cl ( Alternate ) Central Scientific Instruments Organization ( CSIR ), SHRI M. R. KATARIA Chandigarh Automatic Electric Ltd, Bombay SHRI S. S. KULI(ARNI SHRI 0. P. Pun1 ( Alternate ) The Oriential Sciencm Apparatus, Ambala Cantt SHRI LAESR~II SAGAR SHRI K. S. GUPTA ( Alternate)
BARMAN

SHRI A. K.

( Continued on pa&e 2 ) @ Copyright 1985 BUREAU OF INDIAN STANDARDS This publication is protected under the In&n Copyright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act

IS:11287 - 1985
( Contiauedfrompugr 1 ) Mmbns SERI P. T. LENDEE The Rqr~sunting Bombay Electric taring, Bombay Supply & Transport Under-

SERI M. A. KARIM ( Afmnot# ) Siemens India Ltd, Bombay SHRI M. M. LOHIA SHRI A. H. THAKORE ( Alfcmotr ) Toshniwal Industries Pvt Ltd, Ajmer S-I S. C. MAEESHWARI Saw B. SIN.~H ( Ahnate ) Directorate General of Technical Development, SERI D. B. MALIK New Delhi SHRI B. N. DAS ( Akrnat~ ) Directorate of Industries Punjab, Chandigarh SHRI NARINDERJIT SIN~B: SHEI PARXXINDER SINQE ( Altemat~ ) British Physical Laboratories India Pvt Ltd, SERI N. K. RAJASEKEAR Bangalore . Directorate General of Inspection, Ministry of SKI N. NARAYANA RAO Defence ( DGI ), New Delhi SHRI D. P. DEIMAN ( Al&mats ) Sharmasonr Sakova Instruments (P) Ltd, New Delhi SRI%1S. SEABXA Directorate General of Supplies & DisposalsSBRI G. K. SIHNA ( Inspection ), New Delhi SH~I ANIL GUPTA ( AIlrrnatr ) Directorate of Industries & Commerce, Madras SERIT. SOMA~UNDARAM SHRI M. RAJA~OPALA~ ( Alternate ) The Motwane Manufacturing Co Pvt Ltd, Nasik SFLRIK. TEAH~ARAJ Road, C. Rly SERIR. VFZWATESWARAN( Alternate) Instrumentaiion Ltd, Kota SERI RAEESH VERXA SHRI S. NEOQI ( A&mats ) Directorate General of Posts 8~ Telegraphs SEIRI R. VISW~ATEA~ Department of Communication, Jabalpur SRRI T. S. VASUDEVAN ( Alfwnak ) Bharat Heavy Electricals Ltd, Bhopal SHRI M. S. WANDALKAR SHRI S. K. KASLIWAL ( Ahmats ) Director General, ISI ( Ex-ofi Mmbw ) SHRI S. P. SACEDE~, Director ( Elec tech ) Secretary SERI 8. K. MAEATA Joint Director ( Elac tech ), IS1

IS : 11287- 1985

hdian Standard
SPECIFICkTION FOR BRIDGE INSULATIONS TESTERS ( MAGNETO GENERATOR TYPE )

0. FOREWORD
0.1 This Indian Standard was adopted by the Indian Standards Institution on 26 February 1985, after the draft finalized by the Electrical Measuring Instruments Sectional Committee had been approved by the Electrotechnical Division Council. 0.2 This standard deals with the hand generator type insulation testers with bridge facilities which is a very convenient instrument for- measurement of (a) insulation resistance, (b) loop resistance of cables or coil resistance, (c) localization of fault in the cables. It comprises of a hand generator, one or more moving coil instrument(s) and a Wheatstone bridge with loop facilities. 0.3 It is recognized that for bridge insulation testers for use in hazardous and stringent environmental conditions, special provisions concerning environmental testing may be necessary. It is recommended that in such cases these requirements should be additionally specified. 0.4 In the preparation the following: JISG - 1301-1957 Committee. ITD - S/XC/l03 Department. of this standard, issued by assistance Japanese has been derived from Industrial Standard

( Draft ) issued by Indian

Posts and Telegraphs of

Speen No. DTD&P ( AIR ) E & I - 317 issued by Directorate Technical Development & Production, Ministry of Defence.

0.5 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, shall be rounded off in accordance with IS : 2-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. *Rules for roundingoff numerical values ( revised ) 3

IS011287 L 1985 1. SCOPE 1.1 This standard covers the requirements of portable bridge insulation testers ( hand operated ) enclosing in the same case a generator having a rated voltage of 100 volts or more. 1.1.1 The scope of.this standard is confined to hand-operated bridge Mains-operated and motor-driven bridge insulation resistance testers. insulation resistance testers may have to comply with additional requirements which do not form part of this standard. 2. TERMINOLOGY 2.0. For the apply. purpose of this standard, the following definitions shall

2.1 Rated Voltage - The open circuit voltage at the tester between the Line and Earth terminals with the selector switch at the Insulation position as assigned by the manufacturer. 2.2 Rated Insulation Resistance - The resistance indicated by the tester corresponding to the scale mark nearest to the scale mark of infinity. 2.3 Effective Range of Measurement - That part of the scale where measurement can be made with the stated accuracy. 2.3.1 The range of insuIation resistance value from l/l 000 up to l/10 of the rated insulation resistance value, shall be termed as first effective insulation range and the range of insulation resistance from l/l0 of the rated insulation resistance to the rated insulatioq resistance value is termed and second effective insulation range. 2.4 Clntral Scale Mark - The scale mark corresponding to l/50 of the rated insulation resistance with the scale values of 1, 2, 5 or an integral power of 10 or multiples thereof. 2.5 Error in Indication - The difference between the indicated value The error is positive and the true value of the quantity being measured. if the indicated vaIue is greater and negative if it is smaller than the true value. 2.6 Ripple Factor - The arithmetic mean voltage. ratio of the ripple magnitude to the

2.6.1 Ripple - The periodic deviation from arithmetic mean voltage. The magnitude of the ripple is defined as half the difference between the maximum and minimum values. - The permanent magnet moving coil indicator or ratio 2.7 Indicator type indicator, used to indicate directly the insulation resistance value and/or the null detection for bridge measurements. ,4

IS:11287 2.8 Scale

-1985

Length - The length of the arc through the tips of the shortest scale mark. In case of multiscale instrument the scale length shall correspond to the longest of all scales.

2.9 Type Tests - Tests carried out to prove conformity with the requirements of this standard. These are intended to prove the general quantities and design of a given type of tester. 2.10 Routine Tests - Tests carried out on requirements likely to vary during production. 2.11 Acceptance Tests - Tests carried lot for the purpose of acceptance of the lot. 3. RATINGS 3.1 The rated voltage and rated from the values shown in Table 1. ,TABLE i
Rated Voltage ( dc Volts ) Rated Insulation Resistance (MQ)

each

tester

to check

out on samples taken from a

insulation

resistance

may be selected

RATING
100 10 20

OF INSULATION
250 200 20 50 500

RE~XSTANCE
500 - 20 __-100

TESTERS
1 000

1 000

200 500 2 000

3.2 The measurable resistance ( Wheat stone Bridge ) shall from 0.01 ohm to l*OM ohm in five overlapping ranges. 4. CONSTRUCTION

be at

least

4.1 General - The tester shall be sufficiently robust to mechanical vibrations and shocks. Its working parts shall in a case which shall be dust-proof and of sufficient strength adequate protection against external damage. It shall vibration test ( 11.9 ) and bump test ( 11.10 ). 4.2 Terminals -

withstand be housed to afford withstand

The following terminals terminal terminal terminal

shall be provided. L connected E EV connecteu to the to the

4.2.1 Line Terminal - The negative side of the generator. 4.2.2 Earth Terminal - The positive side of the generator. 4.2.3 Vurley Earth varley fault test. The

marked marked marked

for the purpose of

1S:11287

- 1985

42.4 Guard Terminal - The tester shah be equipped with guard ring around the line terminal. A guard terminal shall also be provided and electrically connected to the guard ring in case of testers having rated resistance of 1 000 Ma and above
NOTE 1 - The line terminal, guard rmg and guard terminal shall be connected the negative side and the earth terminal to the positive side of the generator.

to

guard ring and earth term& NOTE Z- The line terminal, marked, preferably as L, G and E respectively to distinguish them.
NOTE 3 - More suitably marked terminals may EV for bridge measurements.

shall besuitably as Z, ZZand

be provided to serve

4.3 Switches 4.3.1 Selector Switch - A rotary selector switch for selecting the functions of Insulation test, Loop resistance test and Varley fault test Additional functions, such as shall be provided and suitably marked. discharge continuity and murray loop test may be provided in the same selector switch. 4.3.2. Ratio Multiplier Switch - For bridge measurement a rotary ratio multiplier switch with at least five multiplier position, namely, X O*Ol, X O-1, X 1, X 10 & X 100, suitably marked, shall be provided. 4.3.3 Series Resistance Switches - Rotary switches and/or potentiometer shall be provided for selecting any value between 1 to 9 999 ohms or more in the arms of the wheatstone bridge, which should be indicated suitably. 4.3.4 Resistors - rhe coils of the ratio and series switches shall be non-inductively wound on non-magnetic spools. The accuracy of the resitors shall be within kO.5 percent of their nominal value at 27C. 4.4 Infinity/Zero Adjustment - A suitabIe device shalI be provided to adjust the pointer to infinity in case of ratio-type instruments having rated resistance of 1 OCOMa and above. For single coil instruments, suitable device shall be provided for ad.iusting both zero and infinity. 4.5 Pointer 4.5.1 The pointers shall be light and rigid and so shaped itself to easy and accurate reading. as to lend

4.5.2 The pointer shall have a knife-edge tip and shall extend over the whole length of the short scale-marks, but not appreciably beyond them. 4.5.3 The 0.30 mm. 4.5.4 edge. thickness of the pointer knife-edge shall not exceed top-

The knife-edge of the poiter shall be coloured 6

red on the

4.6 Central Scale Mark - When the scale starts from 0 MQ the central scale mark in the insulation range shall be located approximately in the geometrical centre of the effective range. 5. EFFECTIVE RANGE

5.1 The effective insulation indicator range shall be from the rated insulation resistance down to the one-thousandth of the rated insulation resistance. 6. ROTATIOP SPEED

6.1 The rated speed of rotation of the handle at which the rated terminal voltage is attained shall not exceed 160 rev/min. It shall be ensured that the terminal voltage is within the tolerance specified in 9.2 even when the rotation speed of the handle exceeds these vplues. 7. GENERAL 7.1 Operation REQUIREMENTS of the Tester

7.1.1 The handle of the tester shall work smoothly. It shall preferably fold back into the casing when the tester is not in use. 7.1.2 The friction small as practicable. in the generator system of the tester shall be as

7.1.3 The degree of camping of the moving coil sytem of the tester, that is, the time elapsed till the pointer has been brought to standstill, when a resistance of the value corresponding to the central scale mark of the insulation range is inserted between the measuring terminals under the normal conditions of use as insulation tester shall not exceed three seconds. 8. NORMAL CONDITIONS OF USE

8.1 The tester shall be used on horizontal surface, with handle rotating at the rated speed or above. The external magnetic field at the place should be less than that specified in 11.4.5. 9. LIMITS OF ERROR

9.1 Insnlatioti Range - The deviation of the pointer from the true value marked shall be within &5 percent in the first effective range and f 10 percent in the second effective range. The deviation of the pointer at l/l0 of the rated resistance shall be within -+5 percent. The deviation of the pointer at the infinity and zero or minimum value shall not exceed +0.7 percent of the scale length. 7

IS : 11287 - 1985

switch in Insulation 9.2 Terminal Voltage - With the selector position, the terminal voltage, from rated speed up to 2nd including 150 percent of the rated, speed of rotation marked on the tester shall be: a) within &lo percent of rated voltage corresponding to the rated resistance, and b) not less than mark. 90 percent of rated voltage for the central scale

9.3 Resistance ( Wheatstone ) Bridge Range - The deviation of readings obtained on the wheatstone bridge shall be within the following limits. Range o-1 51 to 1 51 1.0 Q to 10 $& 10 Q, to l-00 Kfi 100 Kfi to 1 Ma f2 Limit 5 10 percent percent &l percent &2 percent given in 9.3 with

9.4 It should be possible to locate faults with accuracy, fault resistance up to 1 Ma.
10. MARRING

10.1 The following particulars shall be indelibly and suitably marked on the tester either on the dial, or the back or sides or in the cover or on the instruction sheet of the instrument, and shall be visible without necessity of opening the instrument: \ a) Serial number and model number of the tester,

b) Rated

voltage and rated insulation

resistance,

c) Speed of rotation, d) Manufacturers name and/or trade-mark,

e) Country of manufacture, f) Symbol OADJ and cc ADJ for devices used for controlling magnetic shunt or adjusting resistance, and the

g) Brief instructions for using the tester and precaution to be taken at the time of using the instrument, and at the time of storing. 10.2 The ciicuit diagram along with detailed provided in the instruction manual. 8 component list shall be

IS:11287 -198S 10.3 The bridge Standard Mark. insulation resistance tester may also be marked with

10.0.1 The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The details of conditions under which the licence for the use of Standard Mark may be granted to manufacturers or producers may be obtai&.d from the Bureau of Indian Standards.

11. TESTS 11.0 General - Tests shall be carried out unless otherwise specified at the standard temperature of 27 & 2C and relative humidity of 65 f 5 percent. 11.1 Type Tests b) Mechanical The following shall constitute the type tests: endurance test ( 11.5 ),

a) Testi for limits of error ( 11.4.1 to 11.4.6 ), c) Insulation resistance test ( 11.6 ), d) High voltage test ( 11.7 ), e) Dust test ( 11.8 ), f) Vibration test ( 11.9 ), g). Bump test ( 11.10 ), and h) Temperature 11.2 Acceptance tests: cycle test ( 11.11 ). The following.shall constitute the acceptance Tests

a) Insulation resistance test ( 11.6 ), b) High voltage test _( 11.7 ), c) Test for limits of error ( 11.4.1 ), and d) Bump test ( 11.10 ). 11.3 Routine Test The following shall constitute the routine tests:

a) Insulation resistance test ( 11.6 ). b) High voltage test ( 11.7 ), and c) Test for limits of error ( 11.4.1 ). 11.4 Test for Limits of Error

11.4.1 Error at Reference Condition - Tests shall be carried out at reference condition to prove conformity to the provisions laid down in 9.1,9.2, 9.3 and.9.4. 9

18 I ll287 - 1985 11.4.2 Error DUS to Variation of Level - A change of 5 degrees in the level of the tester when used as insulation tester in any direction, shall not result in the deviation of the pointer from its initial position exceeding @5 mm. 11.4.3 Error Due to Variation of Ambient Temprrature - The deviation of the indication of the tester shall not exceed &5 percent at the central scale mark for the ambient temperature change by &2OC from 27%. 11.4.4 Enor Due to Excessive Humidity - The error of the tester shall not exceed the limits specified in 9 after an exposure of 24 hours to a relative humidity of 90 percent aird at a temperature of 27 & 2C. Recovee time shall be 24 h. 11.4.5 Error Due to Stray Field - The error of the tester at the Central Scale.Mark shall not exceed -+5 percent of the indicated value, .when the tester is exposed to a magnetic field produced by 400 ampere-turns ( do ) in a coil of one metre diameter. The tester shall be so placed as to make the influence of the field maximum. 11.4.6 Ripple at Measuring Terminal - The ripple factor at the measuring terminal for the insulation measuring range, shall not exceed 10 percent. 11.5 Mechanical Endurance Test

11.5.1 After repetition of the starting ( up to rated speed ) stopping the generator for 10 000 times, there shall be no evident deterioration and impairment in the working of the tester and it shall satisfy the test specified in 9.3. The ON and OFF times shall be at least 3 s and 6 s respectively and in any case time for 1 cycle shall not exceed 12 s. 11.5.2 All switch contacts shall be tested by actual operation of the switches 10 000 times. After 10 000 operations, there. shall be no mechanical deterioration in the working of the switch and the apparatus shall satisfy the accuracy given in 9.3. 11.6 Insulation Resistance Test - The insulation resistance of the tester across the electrical circuit and the containing case and across the electrical circuit and the handle, when measured by applying 500 V dc, shall be not less than the values given below: a) For rated voltage up to and including b) For rated voltage above 250 V The voltage shall be applied for a duration steady reading of the insulation resistance. 10 long 250 V 25 MS& 50 Ma enough to get a

IS : 11287 - 1985 11.7 High Voltage Test - No breakdown, arcing or sparking shall occur when an rms voltage of 2 000 volts is applied between all the electrical circuit connected together and the -case or the handle for a period of 1 minute.

11.8 Dust Test 11.8.1 The chamber for this test shall be capable of maintaining in any region inside it, where the tester may be placed, temperature of 40 f 2C and a relative humidity of not more than 80 percent. 11.8.2 The atmosphere within the chamber shall be agitated so as to keep it loaded with dust particles of such a size as to enable them to pass through a wire mesh IS Sieve 150 - micron with an aperture of 015 mm [ jet IS : 460 ( Part 1 )-1578* 1. The bulk of the material of the dust shall consist of free silice. The concentration of dust shall be determined by means of the device described in Appendix A where the requirment of dust concentration is also specified. 11.8.3 The tester shall be placed in the test chamber for four hours with the atmosphere stirred and the dust shall then be allowed to settle for two hours. The tester shall then be removed from the chamber and shall satisfy the requirements of 9. 11.9 Vibration Test 11.9.1 The vibration test shall be carried out in accordance with IS i !WKl ( Part 8 )-198lt. The vibration severities shall be as given below:. Endurance Procedure Duration Sweep Frequency Range Amplitude Hz h Endurance at resonance 10 - 150 - 10 0*15mm(2g.) 6 frequency in most unfavourable direction. If direction is not known, vibration shall be applied for 2 h in each of the three mutually perpendicular directions. If no resonance is observed, the equipment shall be subjected to vibration sweep at the rate of 1 octave/minute for 2 h along each of the 3 mutually perpendicular axes.
*Specification for test sieve: Part 1 Wire cloth teat sieves ( suond recd.&m ). tBaaic environmental testing procedures for electronic and electrical items Vibration ( sinusoidal ) test. Part 8

11

IS : 11287- 1985 11.9.2 The following other requirements a) Axis of vibration b) Method of mounting : : shall also be applicable: perpendicular axes.

Three mutually

Normal operations attitude with antivibration mountings if provided. Need not be functioning.

c) Functional check d) Resonance search :

The resonance frequency shall be found by sweeping the frequency over the range selected from the table above. After resonance search, the instrumerit shall comply with. the requirements of 9. The instrument shall be subjected to the endurance as specified in the table above. After completion of the endurance, the instrument shall be checked mcomply with the requirements of 9.

6) Endurance

11.9.3 After in 9.

this test, the tester shall satisfy the requirements given

11.10 Bump Test - The error of the tester at the central scale mark shall not deviate by more than f5 percent from the initial value when subjected to Bumn Test as specified in IS : 9000 ( Part 7/Set 2 )-1979* with the following severities:
d

Number of bumps Repetition rate

4000

& 10

2 to 3 bumps 6 ms 400 m/s2 153 m/s ( tolerance & 20 percent )

Duration of pulse Peak acceleration Velocity change

!I.11 Temperature Cycle Test - The tester shall operate without . incurring permanent damage and also satisfy the requirements of 9 when
subjected the temperature cycle for 16 + 8 h cycleas given in 5.1 of IS : 1248 (Part 9)-1983t for temperature cycle limits - 10C to +55X.

*Basic environmental testing procedures for electronic and electrical items: Part 7 Impact test, Section 2 Bump. tSpe+ication for direct acting electrical indicating instruments: Part 9 Test methods. 12

IS : 11287- I!985

APPENDIX A ( Clause 11.8.2 )

DUST, A-l. DUST CHAMBER AND APPARATUS FOR DUST CONCENTRATION MEASURING

CHAMBER

A-l.1 A schematic layout of a typical chamber recommended for use for the dust cycle is shown in Fig. 1. It is designed to ensure uniform and reproducible distribution of dust. The system is completely enclosed A circulating fan F and does not become congested during operation. ( low pressure, high volume, ventilating pattern ) blows air over the pile P where the dust is picked up and carried along into the chamber C. The air velocity decreases in the chamber so that much of the dust falls back into the hopper H from where it returns to the pile, while the air The dimensions is fed back into the fan through the top of the chamber. of the hopper tube are so proportioned that whatever the head of the dust pressure may be, the pile P never completely fills the main air duct. Consequently, the air flow carries away, more or less, a constant amount of dust from a pile which all the time is being replenished.

Flu. 1 SCHEMA-~C LAYOUT OF APPARATWS DUSTCYCLE

USED FORTHE

13

BAFFLES 1

5; EQUAL AND SYMMETRICAL Dus T INLETS

/-

DETACHbiBLE COVER

All dimensions in millimetres.

FIG.2 DETAILSOF APPARATUSFOR MEASURING DUST CONCENTRATION

A-I.2 The arrangement described under A-l.1 may be modified so as to result in a flow of dust loaded air which takes the shape of a rising vertex. For this purpose, four dust jets may be used in a symmetrical configuration. A-I.3 The below: more important details of a typical dust chamber are given 91.5 cm cube 750 watts 7 100 litres/min at a pressure of 3.8 cm Ha0 250-watt, 3 000 rev/ min motor 14

a) Internai size of chamber b) Heater rating c) Fan rating

IS I 11287-1985 d) Inside diameter of hopper pipe dust DUST 2% cm

e) Inside diameter of circulating A-2. APPARATUS FOR

12.7 cm CONCENTRATION

MEASURING

A-2.1 A-simple measuring device is shown in Fig. 2. Dust enters the box through the five circular holes and collects at the bottom of the Far measuring dust doncentration, the device is detachable cover. placed in any representative position yithin the dust chamber. The air is circulated for five minutes and the dust is then allowed to settle down. The amount of dust which collects on the detachable cover during the total test period is weighed and shall be 23 f 25 g.

15

BUREAU

OF INDIAN STANDARDS

Headquarters: Manak Bhavan, 9 Bahadur Shah Zafar Mar& NEW DELHI 110002 Telephones: 323 0131,323 3375,323 9402 Fax: 91 11 3234062, 91 11 3239399, 91 11 3239382 Telegrams : Manaksanstha (Common to all Offices) Central Laboratory : Telephone Plot No. 20/9, Site IV, Sahibabad Industrial Area, Sahibabad 201dlO Regional Offices: Central .. 323 76 17 337 86 62 60 38 43 8-77 00 32

: Manak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002 *Eastern : l/l 4 CIT Scheme VII M, V.I.P. Road, Maniktola, CALCUTTA 700054
Northern : SC0 335-336, Sector 34-A, CHANDIGARH Southern 160022

: C.I.T. Campus, IV Cross Road, CHENNAI 600113 23523 15 twestern : Manakalaya, E9, Behind Marol Telephone Exchange, Andheri (East), 832 92 95
MUMBAI 400093 Branch Offices::

Pushpak, Nurmohamed ShaikhMarg, Khanpur, AHMEDABAD $Peenya Industrial Area, 1st Stage, Bangalore-Tumkur BANGALORE 560058 Road,

380001

550 1348 839 49 55 55 40 21 40 36 27 21 01 41 8-28 88 01 8-71 19 96

Gangotri Complex, 5th Floor, Bhadbhada Road, T.T. Nagar, BHOPAL 462003 Plot No. 62-63, Unit VI, Ganga Nagar, BHUBANESHWAR Kalaikathir Buildings, 670 Avinashi Road, COIMBATORE Plot No. 43, Sector 16 A, Mathura Road, FARIDABAD Savitri Complex, 116 G.T. Road, GHAZIABAD 201001 781003 500001 751001 641037

121001

53/5 Ward No.29, R.G. Barua Road, 5th By-lane, GUWAHATI

54 11 37 201083 37 29 25 21 68 76

5-8-56C, L.N. Gupta Marg, Nampally Station Road, HYDERABAD E-52, Chitaranjan Marg, C-Scheme, JAIPUR 302001 117/418 B, Sarvodaya Nagar, KANPUR 208005 Seth Bhawan, 2nd Floor, LUCKNOW 226001 Behind Leela Cinema, Naval

Kishore

Road,

23 89 23 5251 71

NIT Building, Second Floor, Gokulpat Market, NAGPUR 440010 Patliputra Industrial Estate, PATNA 800013 Institution of Engineers (India) Building 1332 Shivaji Nagar, PUNE 411005 T.C. No. 14/l 421, University P. 0. Palayam, THIRUVANANTHAPURAM 695034

26 23 05 32 36 35 621 17

*Sales Office is at 5 Chowringhee Approach, P.O. Princep Street, CALCU-I-TA 700072 tSales Office is at Novelty Chambers, Grant Road, MUMBAI 400007 *Sales Office is at F Block, Unity Building, Narashimaraja Square, BANGALORE 560002

271085 309 65 28 222 39 71 , New Delhi, India

Printed at Dee Kay Printers,