Directorate
of Electrical Engineering
Naval Headquarters
STATEMENT OF TECHNICAL REQUIREMENTS
380V/415V/440V 50HZ/60HZ 3 PH PRIMARY
AND 230V 50HZ/60HZ 3PH 4 WIRE SECONDARY
CENTRE TAPPED NEUTRAL EARTHED TRANSFORMER
EED5016
Rev Date Details Prepared by Checked by Approved by
0 Nov 06 CDR Ram Chander Capt. Sanjeev CMDE
JDEE Kale DEE V. Karunanithi
PDEE
NOV 2006
i
ii
380V/415V/440V 50HZ/60HZ 3 PH PRIMARY
AND 230V 50HZ/60HZ 3PH 4 WIRE SECONDARY
CENTRE TAPPED NEUTRAL EARTHED TRANSFORMER
EED5016
1. SCOPE. This statement of requirement covers the manufacturing,
testing and onboard commissioning of the power transformers for portable /
domestic electrical equipment for use onboard ships. The transformers should be
designed to meet the characteristics of input supply voltage for the appropriate
load and duty cycle. The design is to cater for the most adverse environmental
and electrical conditions.
2. Quantity. The number of transformers required on each ship will differ
from ship to ship and the exact requirement will be specified in the Tender
Specifications.
3. Input Power Supply. The transformers should be designed to meet
the characteristics of the following input voltage for the rated load and duty
cycle:
3.1 440V, 60Hz, 3Ph
S No Characteristic Description Value
(a) Voltage Nominal Voltage 440V
Load range Tolerance Average
Average Line to Line value of ± 5%
3Ph system
Line to line voltage of single ± 6%
phase of 3phase system
Max. Unbalance 2%
Max. Modulation 2%
Transients (Excluding Spikes)
(Average line to line value for
3phase system)
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a. Frequent Transients
High limit +6%
Recovery Time 0.5 Sec
Low Limit 10%
Recovery Time 0.5 Sec
b. Infrequent Transients
High limit ± 10%
Recovery Time 1 Sec
Low Limit 16%
Recovery Time 1 Sec
(b) Waveform Max. Individual Harmonic 3%
Max. total Harmonic content 5%
(c) Frequency Nominal Frequency 60 Hz
Load range Tolerance ± 2.5%
Constant Load Tolerance ± 0.5%
Modulation 0.25%
Infrequent Transients
High limit + 3.75%
Recovery Time 2 Seconds
Low Limit 3.75%
Recovery Time 2 Seconds
3.2 415V, 50Hz, 3Ph
S No Characteristic Description Value
(a) Voltage Nominal Voltage 415V
Load range Tolerance Average
Average Line to Line value of ± 6%
3Ph system
Line to line voltage of single
2
phase of 3phase system ± 6%
Max. Unbalance
2%
Max. Modulation
2%
Transients (Excluding Spikes)
(Average line to line value for
3phase system)
a. Frequent Transients
High limit
+6%
Recovery Time
0.5 Sec
Low Limit
10%
Recovery Time
0.5 Sec
b. Infrequent Transients
High limit
Recovery Time + 10%
Low Limit 1 Sec
Recovery Time 16%
1 Sec
(b) Waveform Max. Individual Harmonic 3%
Max. total Harmonic content 5%
(c) Frequency Nominal Frequency 50Hz
Load range Tolerance ± 2.5%
Constant Load Tolerance ± 0.5%
Modulation 0.25%
Infrequent Transients
High limit + 3.75%
Recovery Time 2 Seconds
Low Limit 3.75%
Recovery Time 2 Seconds
3.3 380V, 50Hz, 3 Ph
3
S No Characteristic Description Value
(a) Voltage Nominal Voltage 380V
Load range Tolerance Average
Average Line to Line value of ± 5%
3Ph system
Line to line voltage of single
phase of 3phase system ± 6%
Max. Unbalance 2%
Max. Modulation 2%
Transients (Excluding Spikes)
(Average line to line value for
3phase system)
a. Frequent Transients
High limit +6%
Recovery Time 0.5 Sec
Low Limit 10%
Recovery Time 0.5 Sec
b. Infrequent Transients
High limit + 10%
Recovery Time 1 Sec
Low Limit 16%
Recovery Time 1 Sec
(b) Waveform Max. Individual Harmonic 3%
Max. total Harmonic content 5%
(c) Frequency Nominal Frequency 50Hz
Load range Tolerance ± 2.5%
Constant Load Tolerance ± 0.5%
Modulation ±0.25%
Infrequent Transients
4
High limit + 3.75%
Recovery Time 2 Seconds
Low Limit 3.75%
Recovery Time 2 Seconds
4. Output Power Supply. The Output Voltage of the Transformers at
consumer Terminal shall meet the following specifications:
S No Characteristic Description Value
(a) Voltage Nominal Voltage 230V
Load range Tolerance Average
Average Line to Line value of ± 5%
3Ph system
Line to line voltage of single ± 6%
phase of 3phase system
Max. Unbalance 2%
Max. Modulation 2%
Transients (Excluding Spikes)
(Average line to line value for
3phase system)
a. Frequent Transients
High limit +6%
Recovery Time 0.5 Sec
Low Limit 10%
Recovery Time 0.5 Sec
b. Infrequent Transients
High limit +10%
Recovery Time 1 Sec
Low Limit 16%
5
Recovery Time 1 Sec
(b) Waveform Max. Individual Harmonic 3%
Max. total Harmonic content 5%
(c) Frequency Nominal Frequency 50Hz/60Hz
Load range Tolerance ± 2.5%
Constant Load Tolerance ± 0.5%
Modulation 0.25%
Infrequent Transients
High limit + 3.75%
Recovery Time 2 Seconds
Low Limit 3.75%
Recovery Time 2 Seconds
5. Scope of supply. The following ratings of transformers will comprise the
scope of supply for one ship:
5.1 2.5 KVA Δ/Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral
output.
5.2 5 KVA Δ/Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral
output.
5.3 10 KVA Δ/Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral
output.
5.4 20KVA Δ/Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral
output.
6. Design Requirements.
6.1 Winding. The windings of the transformers should be double wound,
dry type and naturally air cooled. The transformer shall conform to specification
NES 539 (section 6), NES 535, NES 537 and other naval specifications as
applicable. The winding should be so carried out to meet the following
requirements:
6.1.1 Primary Voltage : 380V/415V/440V, 50Hz/60Hz, 3 Ph.
6.1.2 Rating : 5KVA to 20 KVA
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6.1.3 Primary Winding : Delta connected.
6.1.4 Secondary Winding : Star connected three phase terminal output. Centre
point of secondary centre tapped as neutral (two leads). Five connections should
be brought out i.e. one each for three phases and two neutral lines.
6.1.5 Secondary Voltage: The output Voltage between any one of the three
phases and neutral line should be 230V, 50Hz/60Hz.
6.1.6 Electrostatic Screen. The transformers are to be fitted with an
electrostatic screen (for isolation of primary and secondary winding) between
each higher voltage winding and lower voltage winding. It is to comprise a single
turn of copper or aluminum foil but must not form a closed loop. A connection is
to be brought out so that the screen can be connected to the earth stud within the
transformer casing.
7.0 Permissible Temperature Rise.
7.1 Winding. The Max. Permissible temp. rise is 80 0C for Transformer of
“F” class insulation when operating at Max. ambient air temp of 55 0 C. The
Temperature rise shall be measured by resistance method.
7.2 Cores. The Temp. rise is in no case to reach such a value that there
is risk or injury to any insulation material on adjacent parts.
8 Regulation. The regulation at 0.8 P.F should not be more than 3.3%.
9 Inrush Current. The saturated reactance of the primary winding of a
transformer is not to be less than 4.2 Fp /K Ohm per phase. The Primary winding
factor Fp=3 for a Delta connected Primary winding and K is the total KVA rating
of a transformer as specified. In the TSPs. The saturated reactance is to be
calculated as follows:
80 f N2A
Xt = X 10 10 Ohm/ Phase
Where LN : no. of turns in Primary Winding
7
A : Mean cross sectional area of the coil formed by the Primary
winding (mm2)
L : Length of the Winding (mm)
F : Supply Frequency (Hz)
10. Technical Requirements
10.1 Power Factor: 0.8 lagging
10.2 Performance: The Transformer shall be capable of giving its full
rated output continuously or at any other specified loading cycle, within the
normal ambient air temperature and steady state tolerance of electrical supply
conditions, without exceeding the permissible temperature rise of its winding (i.e
class F insulation – 80 deg C) and regulation (3.3%) requirements as specified in
clause 7.1 above. The tolerance of electrical performance of transformer are to
comply with BS 3399.
10.3 Short Circuit Protection. The transformer is to be so designed that
whenever being supplied at the upper steady state limit of input voltage, it can
withstand a short circuit at the output terminals in accordance with the
requirement of BS 3399.
10.4 Self Induced Noise and Vibration. Care is to be taken in the design
and manufacture to ensure that airborne noise and structure borne vibrations
produced by the transformer are reduced to as minimum as possible. Target
figures for noise and vibration levels and methods of taking measurements are
given in clause 0503 of specification NES537. The self induced airborne noise
level and vibration level not to exceed 60 dB. The other general requirements for
the design of electro technical equipment are given in specification NES501.
10.5 Connecting cables. All connecting lead/cables used within the
transformer enclosure should be of LFH type.
11 Construction.
11.1 Laminations. Laminations are to be of cold rolled grain orientated
steel, the grade being selected to give minimum losses, size & weight. The
laminations are to be tightly clamped to reduce noise emission and all bolts
passing through the magnetic circuit are to be effectively insulated.
8
11.2 Insulation. The design of the Transformer should be “F” class. The
insulation material of winding is to include a minimum thickness of 0.5 mm of
mica or micanite or other approved insulation appropriate to the insulation class
between one winding and any one of the following parts:
(a) Core
(b) Another winding
(c) Earthed screen
11.3 Enclosure. The Transformer Enclosure shall be fabricated of MS sheet
of 14 SWG.
11.4 Enclosure Protection. IP23 Drip proof construction protecting water
ingress up to ± 600 of angle.
11.5 Impregnation. All windings are to be impregnated with a thermosetting
varnish by either of the following method:
11.5.1 Vacuum/pressure impregnation and bake, plus one dip and bake.
11.5.2 Hot dip and bake –three times.
11.5.3 A smooth even finish of the windings is essential and an air drying
finishing varnish may be applied after the impregnation process to achieve this
finish.
12. Earthing. The transformers are to be fitted with a double ended
threaded M 10 earth stud in accordance with NES 501. It is to be fitted through
the casing of the transformer, adjacent the cable entry plate for the secondary
winding, and labeled accordingly. The earth stud within the transformer case is to
provide the earthing for Electrostatic screen and screening of cables, if fitted.
13. Terminal Arrangement. The transformers are to have their terminals
sited above the core and accessible by removal of the top cover. The higher and
lower voltage terminals are to be disposed so that neither the supply and
outgoing cables, nor the terminal connections to the higher and lower voltage
windings, cross each other or form inductive loops. The terminal arrangements
must be capable of withstanding the throughfault conditions. Bolted type
terminals and crimping sockets of electrolytic copper are to be provided for all
incoming & outgoing cables.
14. Cable Glands. The cable glands of mild steel for body and naval brass
for nut for incoming and outgoing cable should conform to specifications
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mentioned in DGS/EED/VI/1535/R6 and NES 514. The glands for incoming &
outgoing cables are to be fitted on opposite ends and do not pass each other
across the terminal board. The size of the cable gland shall be indicted at the
time of approval of binding drawings.
15. Shock Standards. The transformer should conform to NSS II BR 3021
shock standards.
16. Vibration Standard. 533 Hz conforming to JSS 55555.
17. Cooling. Natural air cooled.
18. Shock Mounts. The transformer will be deck mounted on suitable
shock mounts. The supplier should also supply suitable S/V mounts and quantity
and pattern No. of mounts be indicated in the drawings.
19. Dimension & Weight. The max. overall dimensions & weight shall be
kept to minimum without compromising the efficiency of the transformer.
20. Lifting Arrangement. Suitable lifting arrangement be provided on top
of the transformer.
21. Efficiency. During the final stages of the temp. rise tests for the
equipment, when temperatures are study, the output and input powers are to be
measured(by wattmeter) to enable the equipment efficiency to be calculated. The
efficiency is to be calculated during full load trials of the transformer in
accordance with BS 3399. The efficiency shall be 97% and above.
22. Tests. The transformer is to be submitted for testing on approval of
drawings within three months of the placement of order. The transformer will be
subjected to following tests:
22.1 Type Test. One transformer from each rating is to be subjected to type
testing as per Joint Services Specification JSS 55555. The type tests required to
be carried out are listed at clause 0502 of NES 537. The transformers which are
not required to be type tested are to be subjected to routine tests listed at clause
0508 of NES 537.
22.2 Environmental Tests. One of each rating of transformer will be tested
for the following environmental tests:
SNO. TEST SPECIFICATION TEST
CONDITION/SEVERITY
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(a) Vibration JSS 55555Test 28 533 Hz
(b) High Temperature JSS 55555Test 17 550 C for 16 Hrs.
Procedure 5, Test
Condition ’G’
(c) Damp Heat JSS 55555Test 10 400 C – 95% RH for 16
Hrs.
(d) Drip proof JSS 55555Test 11 Vertical Water drip 1 mtr
height for 15 min.
(e) Mould Growth JSS 55555Test 21 290 C 90% RH mould
growth chamber for 28
days.
(f) Bump JSS 55555Test 5 1000 bumps40G,
6m/sec
(g) Shock/Impact As per BR 3021, As per laid down
NSS II grade. specifications
(h) Inclination/Tilt AS per NES
1004(Data sheet:36)
(j) EMI/EMC MIL STD 461C/E
22.3 Test Results. The results of the type tests are to be compiled into a
report. The results should include oscillographic records taken during the tests.
The tests are to be carried out on rated voltage and frequency.
23. Sea Way Conditions. The equipment shall be capable of efficient and
unrestricted operation without any deviation from its normal operating parameters
under following conditions.
23.1 Ship Motion:
(a) Roll Max. +/ 300 with 10 sec Operational
0
(b) Pitch Max. +/ 10 with 20 sec Operational
0
(c) List Max. 20 from vertical (permanent) Survival
(d) Trim Max. 50 Survival
23.2 Environmental Conditions. The equipment offered for marine
application shall achieve specified output and function smoothly under tropical
conditions. It shall withstand air contamination through oil, salt and other
contaminants associated with the marine environment. The equipment shall
operate under the following environmental conditions:
SNo. CONDITION NORMAL CLOSED DOWN
(a) Temperature
Storage 0 to 700 C
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Operating 0 to 550 C
(b) Relative Humidity Up to 100%
at 38 deg C
(c) Time Continuous Up to 48 hours.
24. Painting. Powder coating as per IS 5 code 632 grey colour.
25. Tally & Diagram Plate.
25.1 All tally and diagram plate shall be of aluminum oxidized .
25.2 A diagram plate indicating the details of connection is to be procured
/affixed on each long side of transformer plate.
25.3 Size of tally plate, diagram plate, danger plate etc. and their letters shall
conform to NES 723.
25.4 The information mentioned below are to be indicated on the tally plate:
(a) Rating in KVA
(b) No load voltage (HV & LV)
(c) Current in Amps(HV & LV)
(d) Percentage Impedance
(e) Total weight
(f) Frequency
(g) Class of Insulation
(h) Temperature rise C deg
(j) Type of cooling
(k) Purchase order and date
(l) Year of manufacturing
(m) Makers serial number
(n) Terminal plate indicating various output voltages
(p) Earth Terminal
(q) Danger tally voltage (RED)
(r) Connection diagram plate
26. Inspection Authority. DQA (WP)/DQAN
27. QAP. The manufacturer should submit a copy of Quality Assurance Plan
to IHQ MoD (N)/DEE/DQAN for approval within four weeks of LOI.
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28. Information to be supplied while Tendering. The manufacture should
furnish the under mentioned details of transformer at the time of tendering:
(a) Tender Drawing. Tender Drawings are to comprise three clear
prints of the outline of the transformer, showing approximate overall
dimensions and proposed fixing arrangements. The estimated total weight
should also be given.
(b) Voltage ratio at noload.
(c) Noload current
(d) Fullload losses(fixed, copper and total)
(e) Efficiency (at full load UPF and halfload UPF)
(f) Regulation (at UPF and 0.8 PF lagging)
(g) Method of voltage control to meet any special requirements for
regulation which cannot be obtained by the inherent regulation of the
transformer.
(h) Maximum allowable temperature rise in deg C.
(j) Output at abnormal ambient temperature, if applicable.
(k) Class of insulation.
29. A brief specification of the equipment offered is to be submitted, together
with confirmation that all the transformers will conform in all respects to the
Procurement Specifications and relevant specifications or details of all proposed
departures from the requirements of these documents.
30. Earth Screening Label. All double wound transformers which are self
contained in their own enclosure are to be fitted with earth screening labels just
below the tally plate to read as: “SCREENED TRANSFORMER”.
31. Binding Drawings and Documents. The format and content of
documentation being provided should be as per JSS 025101 and EEDS048.
In addition to the hard copy the documents be also supplied in the form of CD
ROM. Documentation shall be presented as per the table below.
(a) Equipment Manual 10 nos.
(b) Installation specification 08 “
(c) CPIL/PIL 18 “
(d) Shop Trial Report 08 “
Test certificates
(e) As fitted drawings
(i) Velographs 02 “
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(ii) Paper Prints 13 “
(f) CD ROM 02 “
31.1 Binding Drawings. Following binding drawings are to be submitted to the
designated authorities for approval:
(a) Overall dimension of the equipment
(b) Mounting arrangement
(c) CG of the equipment
(d) Terminal connection details
(e) Circuit diagram details as per clause 1002 of NES 535.
(f) Part list indicating description, qty, part number, material and
makers name etc.
(g) List of tally plates.
(h) Details of S/V mounts.
(j) Details of Design Specifications.
(k) Details of windings (Gauge, no. of turns, weight, insulating material
etc.)
32. Product Support. The manufacturer should submit product support
certificate for a period of 15 years.
33. On Board and Base & Depot spares.
33.1 Onboard Spares. An itemized list of OBS and special tools which will be
supplied with the main equipment, are to be furnished along with the quotation
for the main equipment. The OBS shall cater for onboard maintenance routines
and possible repairs by ship’s staff. The OBS should include the following:
(a) All spares required for exploitation up to 2 years.
(b) One set of generalpurpose maintenance tools.
(c) One set of special tools required for disassembling /assembling of
components to carry out repair by replacement.
33.2 B&D Spares. Base & Depot spares recommendation is to cover
maintenance /overhaul requirements for 5 years including two refits. Itemised
cost of B&D spares are to be forwarded with the main offer.
34. Governing specifications. Following are the relevant standards:
(a) BR 3021 shock Requirements
(b) JSS 55555 Environmental test methods for electrical &
Electronic equipment
14
(c) EED/DGS/1535/R6 Cable Glands
(d) IS 5 Powder coating painting
(e) NES 723 Tally Plate
(f) DEF STAN 08107 Earthing
(g) MIL STD 461 C/E EMI/EMC
(h) DEF STAN 07224 Material & finishes
(j) DEF STAN 07226 Electrical Testing
(k) NES 581 Electronic components Practice.
(l) NES 539 Guide to design the supply systems for
Portable equipment
(m) NES 535 Requirements for transformers for power
Services.
(n) NES 537 Requirements for testing of the transformers.
(p) NES 501 General requirements for the design of
electrotechnical equipment.
(q) NES 511 Requirements of electrical testing of equipt.
(r) BS 3399 Specification for transformers for use in ships.
(s) BS 5629 Insulating varnish containing solvent.
(t) IS Equipment Enclosure.
(u) EEDS048/ Preparation of documents and drawings.
JSS025101
35. Warranty. The Transformer assembly is to be guaranteed for stipulated
performance for 24 months after commissioning. The equipment supplied shall
be warranted against defects arising due to malfunction through design faults,
inappropriate material, bad production and nonconformance to specifications.
Any expense on account of repair/supply of spares against guarantee defects is
to be borne by the supplier.
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