Reliability of Electronic Cards of Three Phase Locomotives · 2019-10-17 · numbers are provided....

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Reliability of Electronic Cards of Three Phase Locomotives R. N. Lal*, Sandeep Srivastava** and V. K. Singh***

Abstract

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Indian Railways imported 22 WAG9 locomotives and 11 WAP5 locomotives from M/s. ABB, Switzerland in 1996-97. Later on, CLW started manufacturing these locomotives by procuring Power Converter, Auxiliary Converter & Control Electronics from ABB, Switzerland. These equipments were subsequently indigenised by M/s. BTIL, M/s. NELCO, M/s. BHEL and M/s. CGL through transfer of technology. The failure of electronic cards of Power Converter, Auxiliary Converter and Central Electronics has always been a source of concern which has not only been adversely affecting the reliability but availability also of these locomotives. An effort through this paper has been made to analyse the causes of failures of electronic cards, validate it through test trials and suggest remedial measures to reduce the failures.

1.0 Introduction:

There are 05 locations in which 29 types of electronic cards, totalling 113 in numbers are provided. There are three main equipments in which these cards have been used in the locomotives. These electronic cards form part of Control Cubicle of Power Converter, Gate unit & Gate unit power supply, Auxiliary Converter and Vehicle Control Unit. The cards are identical for WAP5, WAP7 and WAG9 class of locomotives.

1.1 Control Cubicle for Power Converter (SR):

There are total 13 types of electronic cards in power converter control cubicle (figure-1). Mainly classified as power supply card, single board computer (processor) card signal conditioning cards, NS/AS controller and peripheral card, GTO optical pulse card, bus coupler card, analog & digital I/O cards. These cards are placed in a dust proof housing as shown below.

Figure-1: Power converter electronic cubicle

Apart from the above, gate units (GU) and power supply for gate units (GUSP) are housed separately in contactor cubicle (figure-2). * Sr.Executive Director/Electric Loco/RDSO/Lucknow **Director/ Director/Electric Loco/RDSO/Lucknow ***Dy.Director/ Electric Loco/RDSO/Lucknow

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GU GUSP

Figure-2: GU and GUSP

1.2 Auxiliary Converter (BUR):

There are five cards for controlling auxiliary Converter (figure-3). These are power supply card, controller card (processor card), chopper / WRE/GG controller cards, auxiliary interface card and bus coupler cards. Besides this there is gate driver card of WRE (inverter) module.

Figure-3: Electronic cubicle of BUR

1.3 Vehicle Control Unit (VCU):

There are two cubicles provided in three phase locomotive in which cards for vehicle control are housed (figure-4). Total 11 types of cards have been used in each VCU. These are power supply cards, digital and analog I/O cards, single board computer card, bus administrator cards (for vehicle bus & train bus), bus coupler cards, signal routing board and display & diagnostic computer cards.

Figure-4: VCU

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2.0 Failure analysis of cards:

Failure details of electronic cards of SR, BUR and VCU have been collected from loco sheds. The failures of various cards of last five years are shown in table-1, 2, 3 and 4 in annex-I. From the analysis of the cards it is clear that there are 11 types of cards (given in table-A below) which have contributed approximately 70-75% of the total card failures of the equipment in last three-four years: Item 1 to 4 contributes maximum failures followed by 5-11.

SN Name of card Type of card Slot Name

1 NS Controller / AS Controller PPA988B02 MN/IJ slot of SR

2 Gate unit GVA 587 A01 SR

3 Digital I/O board URB512D15 J/L/O/Q slot of SR

4 Power Supply KUC153A01 Back plane BUR

5 Signal Conditioning Board UAB630A36/

91/93 A/B/C slot of SR

6 GTO optical pulse card AFB635B08

12/34 slot of SR

7 Single board computer PPB622B01 U slot of SR and G/N/S slot of VCU

8 Digital I/O board URB177D15 W slot of SR

9 Power Supply KUA 915B01 XYZ slot of SR

10 Diagnostic computer PPB624A01 U slot of VCU

11 Display computer (DDA) PPB908A01 HI/H slot of VCU

Table-A: Cards contributing most of the failures

2.1 Component wise analysis of failures of these cards has been done and are

summarised in table-B,C and D which are given as under.

S.N. CAUSE PPA988B02

AS/NS Controller

(SR)

GVA 587 A01

Gate Unit

(SR)

URB512D15

Digital I/O Board

(VCU)

KUC153A01 Power supply

(BUR)

1 No Fault Found 21.5 % 10% 27.2%

25%

2 Electrolytic

Capacitor

12.3% 57.1% -

50%

3 Diode/Z diode 9.2% - - -

4 IC 29.2% - 4.5% -

5 Resistor 18.5% - - -

6 Reed Relay 24V - - 40.9% -

7 PS 2022 - - 13.6% -

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8 Fiber optic

transmitter

QFBR-1478C

(A101)

- 27.7% - -

9 Others 9.2% 5.2% 13.6% 25%

Table-B: Component wise failure analysis of cards at s.no.1 to 4 of table A

SN CAUSE UAB630A36/ 91/93

Signal Conditioning

Board (SR)

AFB635B08 GTO optical

pulse Card (SR)

PPB622B01 Single board

Computer (SR & VCU)

URB177D15 Digital I/O board

computer (SR)

1 No Fault Found

56.3% 27.3% 30% -

2 Electrolytic capacitors

18.75% 45.4% 20% 33.3%

3 IC 6.25% - - -

4 Fiber Optic transmitter

QFBR-1478C (A101)

- 27.3% - -

5 EPROM - - 20% -

6 Track Fuse - - - 50%

7 Others 18.75% - 30% 16.7%

Table-C: Component wise failure analysis of card at S .No. 5,6,7 &8 of table A

SN CAUSE KUA915B01 Power Supply

(SR)

PPB624A01 Diagnostic computer

(VCU)

PPB908A01 Display computer (DDA)

(VCU)

1 No Fault Found 16.7% 18.2% -

2

Electrolytic

capcitor

- 9% 50%

3 IC - 45.5% -

4 Hybrid module 50% - -

5 Transistor 16.6% - -

6 Battery (3.6V) - 18.2% 25%

7 Others 16.6% 9% 25%

Table-D: Component wise failure analysis of cards at S.No. 9,10 &11 of table A.

2.2 Shed wise and make wise failure analysis of these cards of last three years have been done. The analysis is given in table-5 and 6 of annex-II.

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3.0 Conclusions from the failure analysis: 3.1 General Observation:

From the above analysis (table-B, C & D) it is clear that electrolytic capacitors are the major cause of failures of cards. The other major causes are failures of EPROMs, fibre optic components and hybrid module. As per the analysis the failure cases are high after a period of 4 years of service which can be seen from table-E below.

SN Name of Card Type of Card No. of Card failures

Within 4 years Within 4-8 years

1. NS Controller/AC Controller Card

PPA 988B02 35% 65%

2. GUSP GVA 587A01 29% 71%

3. Digital I/O Board URB 177D15 7% 93%

4. Gate Unit KYA 924D01 15% 85%

5. Power Supply for SR

KUA 915B01 40% 60%

6. Power Supply for BUR

KUC 153A02 47% 53%

Table-E: Age wise failures of cards

It is observed that the failure of electrolytic capacitor shows rising trends after 4 years of service mainly due to higher ambient temperatures in India. M/s BT has informed that the rising trend of failure of such capacitors in European countries has been observed after 9 years of service. Temperature measurements were carried out at ½ inch away from the cards in locomotives which shows 15oC higher temperature above ambient in power converter cards. The temperature rise in the vicinity of auxiliary converter cards and VCU cards are comparatively less (table-F). High rate of failure of power converter cards as compared to auxiliary converter and VCU cards also substantiates it (table-1 to 4 of Annex-I). It seems that the electronics of these three phase locomotive has been designed for European climatic conditions (85oC class components have been used) where maximum ambient temperature goes up to 40oC. In Indian conditions where ambient goes up to 50oC, the temperature in the vicinity of cards goes up to 65oC, which means temperature of components may be rising beyond 85oC particularly during summers against the limit of 75oC for 85oC class components (margin of 10oC is required for better life and reliability of components). This has been causing premature failures of components and erratic behaviour of components, especially during summers, which results in transient failures of cards. This is evident from the failure analysis (table-B, C & D) where cases of NFF (no fault found) are maximum and are generally more during summer.

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Sl No

Location

Ambient Temp

Machine Room Temp

Temp 1/2 inch away from card

Temperature rise

1 SR2 43 48 58 15

2 BUR2 43 48 52 9

3 BUR3 43 48 54 11

4 VCU2 43 48 50 7 Table-F: Temperature recorded near cards of WAP7 locomotive

In Indian conditions the life of the electrolytic capacitors is expected around 6 years (table-G and figure-5). Hence there is need to rehabilitate the cards by changing electrolytic capacitors and other components such as EPROMs & fibre optic components after six years.

Figure-5: Life expectancy of electrolytic capacitors

At 1.5 Times Ripple Current

Expected Life of capacitors at ambient temperature and at 1.5 times Ripple Current based on above graph.

at 40 ºC expected life (Hrs)

Rehabilitation required after year





10A 22mm dia Ir x 1.5

90000 12.84 48000 6.85 25000 3.56

Table-G: Life expectancy of electrolytic capacitors

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3.2 Card Specific failures & their remedial measures: 3.2.1 NS/AS controller card (PPA988B02):

Figure-6: PPA988B02 card

There have been increase in failures of this card in last 3 years (table-1). Make wise analysis of these cards (table 6) indicates that the failures are in BTIL make who have indigenised these cards in 2001 whereas BHEL and NELCO are still importing this card. Shed wise failures of this card (table 5) also indicates that the failures are predominantly in Ajni and Lallaguda sheds where BTIL make NS/AS controller card mostly manufactured after 2001 have been provided in the locomotives. After detailed analysis it is found that IC14C88, zener diodes and resistors associated with this IC are failing (table-B). This is due to non implementation of a modification of ungrounding pin no. 8 and 11 of the IC by M/s. BTIL in their indigenous version (Figure-7), which was done by OEM in 1998.

Figure-7: Ungrounding of pins in IC14C88

With the grounding, IC picks up 15 V supply faster and during this time inputs to the IC may be in undetermined state and can in cases causes output to go high which leads to premature failure of IC, zeners and resistors. The modification of ungrounding pin no. 8 and 11 is in progress which will eliminate this failure.

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3.2.2 Gate Unit Card (GVA587A01)

Figure-8: GVA587A01

There have been failures of electrolytic capacitors mainly in Gate Unit cards after a period of 5-6 years as evident from table-E and table-5 (failures are more in Gomoh shed where these cards are comparatively older). Premature failure of fibre optic transmitter (QFBR1478C, component A151) (figure-9) (table-B), recently supplied in Gate unit cards, is also cause of concern. This component is failing due to manufacturing problem of OEM, M/s AVAGO. As per the investigation, this component is failing due to ‘back line effect’ where the output dB level of the component goes down prematurely within a short span of time. It has been learnt that manufacturing of the wafer of this optical transmitter was shifted from USA to Singapore and final packaging of this optical transmitter was done in Phillipines from January 2005 and onwards. Earlier, after manufacturing, screening test of this component, comprising of burn-in cycle of 5000 hours from -25OC to +75OC used to be done in USA. This practice was stopped when manufacturing was shifted to Phillipines. Later on, this practice was reintroduced in the end of year 2007 at Phillipines. Hence the lot supplied between Jan 2005 to Sep 2007 is the source of this problem. RDSO has issued a testing procedure by means of which output level of this component can be measured inside the locomotives in simulation mode and if found below -18 dBM, the component has to be replaced. This will eliminate the problem of premature failures of QFBR1478C in suspected lot. It can also be used to weed out over aged defective fibre optic transmitter.

Figure-9: Gate Unit

QFBR1478C

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3.2.3 Digital I/O Board Card (URB512D15)

Figure-10: Digital I/O board

As evident from table-6, the main cause of failure of this card is failure of 24V reed relay. This relay controls closing (holding) and opening of VCB thereby making and breaking inductive current of VCB coil. This results in flashing and welding of contacts of the relay. The existing RC network (R=220 ohm, C=0.1 microfarad) is not sufficient to prevent arc across the contacts while opening the VCB. After detailed study the RC network has been modified (R=100 ohm with diode across it, C=0.11 microfarad). Two cards having two N/O interlock in series and modified RC network in reed relay and two cards having two N/O interlock in series and existing RC network in reed relay are put on trial at ELS Lallaguda. These modified cards are under trial at Lallaguda shed since May’09.

3.2.4 Power Supply Card (KUC153A01)

Figure-11: KUC153A01

3.2.4.1 There have been cases of intermittent tripping of this power supply card of

auxiliary converter on line particularly in summers. The problem was analysed in detail and it was found that in due course of time the cover of electronics module of auxiliary converter got changed where the air circulation openings were reduced, resulting in temperature increase near the card (figure-12). The cover has been modified to have more air circulation (figure-13), which have helped in eliminating the problems in modified locos.

Figure-12: Original Cover Figure-13: Modified cover

24V reed relay

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3.2.4.2 The main cause of failures of this card is electrolytic capacitors (table-B). This card is being imported by all TOT partners so far. An effort has been made to develop functionally equivalent power supply card indigenously. M/s BHEL has developed this card with better output quality and simplified protection logic. One card is under trial at ELS Ajni since Mar’09 and working satisfactorily. M/s BTIL and NELCO are in the process of developing this card indigenously.

3.2.5 Gate Driver card of WRE (Inverter Module) of Auxiliary Converter:

Gate driver card has been the major cause of failures in WRE modules over the years (table-H).

S. N

Failures in WRE modules

TOTAL

2006-07 2007-08 2008-09

1. GD Card 51 71 31

2. Contact flash 23 2 4

3. GTO 13 21 57

4. Other - 26 21

5. Total Failure 87 120 113

6. Holding 451 546 675

7. FRPCPY 19.3% 22% 16.7%

Table-H: Failures of WRE GD card

Make wise GD card of WRE failures are tabulated in table-I.

S. N

Make 2006-07 2007-08 2008-09

No. FRPCPY No. FRPCPY No. FRPCPY

1 BTS 13 11.5% 11 9.7% 9 7.9%

2 BTIL 19 11.3% 33 15.9% 5 1.9%

3 BHEL 9 9.7% 16 13.3% 13 6.7%

4 AAL 7 30% 3 13% 2 8.0%

5 CGL 1 3.3% 2 6.6% 1 3.3%

6 NELCO 2 9.5% 9 34% 1 3.7

8 TOTAL 51 71 31 4.6%

Table-I: make wise failures of GD cards of WRE

3.2.5.1 Analysis of failures of GD card:

Following are the main reasons and action taken to avoid the failures of GD card:

3.2.5.1.1 Hybrid PCB

Several quality problems like improper component mounting, no coating / cleaning, several rejections at incoming stage / testing were observed in hybrid PCB procured from the OEM (Switzerland).

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Improved (Indigenous) Old (OEM not known)

Figure-14: Hybrid of WRE

This hybrid PCB has now been produced locally by BTIL using the same facility as for the other MICAS S2 cards and quality has been significantly improved (figure-14).

3.2.5.1.2 Zener diode

Frequent failures of zener diode were found in failed site returned WRE GUs. (Part BZX55 3.6V 0.5 W, Drawing no. XN400249P0004, position no: V214 and V414). The power rating of zener diode (position 214 & 414) has been increased. The alternate part is Silicon Planar Power Zener Diode BZX85C3V6. This is a 1.3 W zener diode as against 0.5 W of earlier one.

3.2.5.1.3 Improvement in cooling of GD card

Cover has been modified as shown in figure-15 to improve the cooling.

Existing Modified

Figure-15: Cover of WRE GD card

3.2.5.1.4 Improved air cooling in BUR

At present, fans in power cubicle turns ON at 50±5ºC and turns OFF at 35±6ºC (hysteresis). Considering Indian conditions, it is considered to keep the fans of power compartment in continuously ON condition. (Same fans used to cool auxiliary electronics, SR electronics and VCU is kept continuously on). Now this fans have been made continuously ON to improve the cooling.

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Figure-16: Fans in BUR

3.2.5.2 Analysis of GTO failures of WRE module: The failures of GTO have shown an increasing trend in 08-09 (table H). The

make wise and shed wise failures of GTO are tabulated in table-J.

S.N. Make Failures (2008-09) BUR Population FRPCPY

1. BHEL 30 194 15.46%

2. BT/S 13 113 11.50%

3. BTIL 5 264 01.89%

4. CGL 3 30 10.00%

5. AAL 3 25 12.00%

6. NELCO 3 27 11.11%

Total 57 675 08.44%

S.N. Shed Failures (2008-09) BUR Population FRPCPY

1. AQ 09 180 5%

2. GMO 10 201 5%

3. GZB 16 138 11.6%

4. LGD 22 156 14.1%

Total 57 675 8.44%

Table-J Make wise and shed wise failure of GTO/Diode of WRE module

It is clear from the above that the GTOs are failing in BHEL make BURs of new locomotives homed at Lallaguda and GZB shed. The failures are also in BT/S make in GMO & GZB shed which are old. The matter has been taken up with M/s BHEL and it is learnt that the failure of fibre optic transmitter (QFBR1478C) is the main reason of failure of GTOs. This component is of Avago make. RDSO has issued SMI No. 0256 dated 21.05.09 for testing of this component (para 5.1.2(v) of the SMI).

4.0 Action plan to improve the temperature around card surroundings:

As already discussed earlier, higher ambient temperature in the vicinity of cards is one of the main reason of high rate of failure of electronics in three phase locomotives. Following action plan is recommended for reducing the temperature in the vicinity of control electronics which have been finalised based on test trial in the locomotives.

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4.1 Modified heat sink of power converter electronics (ALG rack):

The design of heat sink of traction converter electronics have been studied and CFD analysis of air flow shows following deficiencies in the design:

The heat sink is of mild steel which is inferior to aluminium heat sink which is commonly used as heat sink material. The earlier design is also not effective as air contact with heat sink is minimal (Figure-17).

The air flow is not uniform across the length of heat sink resulting in hot spots in the middle and opposite end (figure-18).

• .

Heat Exchanger is provided at

back side of cubicle.

Air enters from back side through

4 inch pipe and after cooling heat

exchanger it comes out from top.

2.5 m/s 0.9 m/s

Figure-17: Cooling arrangement of SR electronics

Figure-18: CFD analysis of air flow in heat sink

A modified heat sink of Aluminium has been developed by M/s BTIL and M/s NELCO through some outside agencies (figure-19 & 20) and trials conducted have shown improvement in temperature rise by 6oC near traction converter cards. This design has also made the air flow uniform which can be seen from table-K.

Location Ambient Temp

Temp at card level Temperature rise

Traction converter

near “V” slot

Existing heat sink

Modified heat sink

Existing heat sink

Modified heat sink

51 67 61 16 10

Temperature measurement

Air flow measurement Heat sink

Type Hose pipe side Middle Apposite to Hose pipe end

Existing 1.4m/s 0.3m/s 0.6m/s

Modified 1.6m/s 1.3m/s 1.4m/s

Table-K: Temperature and air flow measurements

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Existing Design Modified Design

Max air passing through outer area Comlete air passing through tubes only

No specific path for air flow, max air passing Specific path for air flow, air is passing through nearby tubes through all tubes

Figure-19: Improvement in SR heat sink by BTIL

Existing design Modified design Figure-20: Improvement in SR heat sink by NELCO

4.2 Another trial was done where heat conducting coating was provided inside the ALG rack housing (figure-21). The trial results have shown improvement in temperature rise by 6oC near cards (table-L).

Figure-21: Heat conducting paint provided inside

ALG housing

Heat transfer coating

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Sl No Location Ambient

Temp Temp at card level Temperature rise

Normal condition

With coating Normal condition

With coating

1 Traction converter near ‘V’ slot

51 62 57 11 6

Table-L: Temperature measurements

4.3 Air conditioners of 2.5/3.0 tonnes capacity has been provided in one loco each at LGD and GZB sheds at MRB outlets which have shown improvement in temperatures rise by 7-8 OC near cards of SR, BUR and VCU electronics (table-M).

Ambient Temp

Machine Room Temp

Temperature at MRB1 locations (AC provided)

Temperature at MRB2 location (w/o AC)

VCU1

SR-1 Electronics

VCU2 SR-1 Electronics

36.5 46.5 39.5 41.7 47.1 48.8

Table-M: Temperature measurements

5.0 Use of better rated electrolytic capacitors having higher operating life:

The capacitors which were prone to failures have been identified for replacement with better rated capacitors having better operating life. This will improve reliability of cards. The details are given in annex-III.

6.0 Effect of dust accumulation and remedy:

6.1 Another problem associated with electronic card is accumulation of dust in three

phase locomotives. The problem of dust accumulation is attributed to less pressurisation of machine room and improper filtering of incoming air to machine room.

6.2 In order to avoid ingress of dust into locomotive, machine room of these locomotives

are pressurised using machine room blowers. The air delivery of machine room blowers first pass through heat sink of electronic cubical of power converter, auxiliary converter, vehicle control unit and thereafter it goes to machine room compartment and finally escapes out through ventilators. It is noted that although WAP5 locomotives is shorter in length by almost 2 meters but it has only 4 ventilators for escaping out the air, whereas WAG9/WAP7 has 6 ventilators even though its machine room size is larger in volume.

6.3 The outlet air velocity in WAP7/WAG9 and WAP5 were recorded to evaluate the

pressure inside the machine room. These results are tabulated in table-N below.

S.N. Location Outlet Air Velocity (m/sec) WAP7 Loco

No.30243

Outlet Air Velocity (m/sec) WAP5 Loco

No.30005 1. Ventilator 1/CAB-1 3.6 10.2 2. Ventilator 2/CAB-1 3.6 10.0 3. Ventilator 1/CAB-2 4.0 8.7 4. Ventilator 2/CAB-2 3.9 9.5 5. Ventilator Centre 4.3 NA 6. Ventilator Centre 4.7 NA

Table-N: Comparison of air velocity in WAP5 and WAP7/WAG9

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It can be seen that the air velocity in WAP5 locomotive at ventilator point is almost twice as compared to WAP7/WAG9 in stationary conditions. Following reasons were identified for less pressure in WAG9/WAP7:

i) Although volume of machine room of WAP7/WAG9 is comparatively larger than WAP5 but same size of machine room blower have been used.

ii) There are six ventilators in WAP7/WAG9 as compared to four in WAP5.

iii) There were noticeable leakages at the joints of suction side of oil cooling blower, traction motor blower and scavenger motors which sucks in air from the machine room (figure-22). Similarly there are leakage points noticed through earth return cable in some locos (figure-23). These defects are persisting in some locomotive right from the beginning due to manufacturing problem.

More trials were conducted by different sheds to evaluate the direction of air flow from the ventilators in WAG9,WAP7 and WAP5 locomotives at different speed with four/six ventilators/ (blocking the two centrally located ventilators). Some of these results are given in annex-IV.

Following interesting results were observed:

i) The air starts flowing into the locomotive through the rear ventilators after 80 kmph onwards in those WAG9/WAP7 locomotives which have six ventilators and the velocity of inflow increases with the increase in speed of locomotives.

ii) The air inflow into the machine room of locomotives from the rear ventilators

starts taking place even at lower speed, if there are leakages in machine room. It can be seen that in WAP-7 Locomotive at 110 Kmph downward in flow of air has increased up to 4.5 m/sec. which brings dust in locomotive where as in WAP5 locomotive air flows out at appreciable speed even at 110 Kmph. It may be appreciated that at higher speed i.e. around 130 Kmph this in flow will further increase bringing in more dust in locomotive. This is one of the main reason that air dust in WAP-7 locomotives are found to be more as compared to WAP-5 during inspection.

6.4 Following action plan need to be taken to arrest the problem of ingress of dust in locomotives –

i) Increase the blowing capacity of machine room blower by 30% and use secondary filters after inertial filters in line with WAG6A locomotives.

ii) Block the centrally located two ventilators in all WAP7/WAG9 locomotives.

iii) Cause immediate action to arrest leakages of air from the machine room other

than through ventilators. Special attention should be given to joints of oil cooling blower and scavenging blowers which are biggest source of problem. It is noted that initially the gasket of OCB was completely round in shape and in single piece whereas right now it comes in pieces which could be the main reason for leakage. CLW should revert back to original design of gasket for both OCB as well as scavenging blowers. Railways should also procure complete gasket and replace it wherever it is required.

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Figure-22: Gap in Oil Cooling Blower

Figure-23: Gap around earth current return cable

7.0 Summary of action plan to improve the reliability of electronics: 7.1 Action plan already issued through SMI/MS and are in the process of

implementation: 7.1.1 RDSO has issued instruction for rehabilitation of cards after six years by

changing electrolytic capacitors and other components such as EPROMS and fibre optic components vide this office letter no. EL/11.5.5/8 dated 22.12.08. RDSO has also issued guideline (no. EL/G/2008/01, Rev’1’ Aug’09) for rehabilitation of these cards indicating the components to be changed during rehabilitation. This also includes use of better rated capacitors as discussed in para 5.0 above. This should be implemented by sheds.

7.1.2 To arrest the failure of IC:14C88 in NS/AS controller card, a Modification Sheet

( MS/0378 dated 29.05.09)) has been issued for ungrounding Pin No. 8 & 11, which should be implemented. This modification needs to be implemented through M/s BTIL. Loco sheds should pursue it with M/s BTIL and get it implemented at the earliest.

7.1.3 To avoid premature failure of QFBR1478C in gate unit of power converter, a SMI

(SMI/257 dated 22.05.09) has been issued by RDSO for checking of dB level of output of the fibre optic transmitter. Similarly to avoid shorting of gate and cathode terminal of gate units, a Modification Sheet (MS/0378 dated 29.05.09)

Air leakage in under frame

No Air leakage in under

frame

Gap on suction side

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has been issued by RDSO for inserting an insulated plate between gate and cathode.

7.1.4 The cover of electronic module of auxiliary converter have been modified to have

more air circulation to avoid intermittent failure of power supply card. RDSO has issued the instructions for implementation in field vide modification sheet no. MS/0372 dated 20.01.09.

7.1.5 The reason of failures of gate driver card of WRE module of auxiliary converter

has been identified. RDSO has issued a Modification Sheet (MS/0372 dated 21.01.09) and letter No. EL/11.5.5/2/BT dated 11.11.08 to TOT partners for doing the following modification in this card:

• Indigenisation of hybrid card

• Improvement in rating of zener diode

• Use of perforated cover on gate driver card

• Working the cooling fans continuously on by shorting thermostat 7.1.6 RDSO has issued SMI No. 0256 dated 21.05.09 for testing of gate driver of WRE

module of auxiliary converter, by which any suspected gate driver card can be tested. Fibre optic transmitter can also be checked as per this SMI to avoid failure of GTOs in WRE module.

7.1.7 To maintain the pressurisation in machine room of three phase locomotives,

RDSO has issued SMI No. 255 dated 08.05.09 for measurement of air velocity at various locations inside the machine room by sheds and to take necessary corrective actions. RDSO has also benchmarked the values of air velocity at various locations inside machine room and at ventilators for newly built locomotives at CLW, which has been advised to CLW vide letter no. EL/11.5.5/5 dated 17.06.09.

7.1.8 To improve the pressurisation of machine room in WAP7 and WAG9 locomotives

and to avoid dust ingress in the machine room, RDSO has issued Modification sheet No. 0380 dated 14.07.09 to block two centrally located ventilators in WAP7 and WAG9 locomotives.

7.1.9 The electrolytic capacitors, which are prone to failure have been identified for

replacement with better rated capacitors having better operating life. This will improve the reliability of cards. M/s. BTIL and M/s. BHEL have been advised (vide letter no. EL/11.5.5/5 dated 15.05.09) for manufacturing of cards with these type of capacitors. All TOT partners have given their technical consent to use these capacitors.

7.1.10 To avoid failure of 24 V read relay in digital I/O board, modified cards with reed

relays having 2 N/O interlock in series and improved RC network along with diode across resistance are running successfully on trial in Lallaguda shed since May/June, 2009. Use of this type of cards with modified reed relays and modified RC networks for relay K250, K251, K247 and K253 have been decided.

7.2 Actions proposed to be taken after field validation trial:

7.2.1 To reduce the temperature near the cards of power converter, the design of heat

exchanger of traction converter electronics have been modified for better cooling. These types of heat exchangers are in field trial. After field trial, regular use of modified heat exchanger will be cut-in in future production and replacement in the existing locomotives. Also for better heat transfer, thermal heat transfer paint

19

(type 20304) has been applied inside SR control cubicle, the temperature rise inside the cards was recorded less as compared to the control cubicle where heat transfer paint was not applied.

7.2.2 For improvement of cooling of electronic cards, a 3 ton air conditioner has been

provided in one loco at GZB shed at machine room blower outlet on experimental basis. The results are very encouraging as an improvement of 7-8 deg. C in temperature rise near cards have been observed. RDSO has prepared specification of air conditioning unit. It is recommended to provide air conditioning units in 10 WAP7 and 10 WAG9 locomotives for extensive field trials.

7.2.3 Functionally equivalent card of power supply card of auxiliary converter has been

developed indigenously by BHEL and is working satisfactorily in field for the last three months. Similarly, power supply card of traction converter is also under development indigenously. M/s. BTIL, M/s. NELCO & M/s. BHEL are in the process of finalizing prototype of these cards. After development of these indigenous cards, the problem of failures of these cards will be eliminated.

7.2.4 RDSO is working on increasing the capacity of machine room blower by 30%

and use of secondary filters after inertial filters in line with WAG6A locomotives to avoid problem of dust accumulation. It is decided that an independent single phase to three phase converter shall be developed to run the MRBs on 65 - 70 Hz frequency so as to increase the capacity by 30%.

The existing machine room blower has already been modified by changing the design of blower impeller and the capacity has increased by 15%. This shall be used at present without secondary stage filters to increase the pressurization of machine room.

References: 1. Report No. RDSO/2007/EL/RM/0123, Rev.0 on issues concerning

reliability / availability of three phase electric locomotives.

2. Report No. RDSO/2008/EL/RM/0127, Rev.0 on repair of Printed Circuit Boards of three phase locomotives.

3. Printed Circuit Hand Book – By Clyde F. Coombs, Jr

4. Printed and Integrated Circuitry (Materials & Process) – By T.D.Schlabach & D.K.Rider

20

Annex-I

SN Name of card Type of card Slot Name

No. of failures

2003-04

2004-05

2005-06

2006-07

2007-08

2008-09

1 Single conditioning board-SLG UAB630A36 A slot 4 1 4 5 11 9

2 Single conditioning board-NSC UAB630A91 B slot 8 10 6 3 3 11

3 Single conditioning board-ASC UAB630A93 C slot 2 3 6 1 7 10

4 Single routine board ARB705B01 D slot 2 0 0 0 3 5

5 AS peripheral board XVA987C22 H slot 3 0 3 3 2 5

6 NS peripheral board XVA986B22 L slot 2 4 7 5 3 9

7 NS Controller/AS Controller PPA988B02

MN/IJ slot

17 (27%)

14 (31%)

27 (37%)

49 (51%)

55 (39%)

75 (41.2%)

8 GTO optical pulse card AFB635B08

12/34 slot 3 2 0 7 18 19

9 Single board computer PPB622B01 U slot 1 1 4 5 11 11

10 Digital I/O board computer URB177D15 W slot 13 6 5 6 10 10

11 Power Supply KUA915B01 XYZ slot 4 3 4 11 14 9

12 Rack 2 1 1 0 3 3

13 Unknown 2 0 4 0 0 4

14 Total 63 45 72 97 140 182

15 Population (SR) 158 196 240 302 370 450

16 FRPCPY (EQPT) 40% 23% 30% 32% 28.5% 40.44

17 Population (Cards) 2370 2940 3600 4530 5550 6750

18 FRPCPY (CARDS) 2.5% 1.44% 1.875% 2% 1.78% 2.70

Table-1: Failures of cards of SR

21

SN Item 03-04 04-05 05-06 06-07 07-08 08-09

1. Gate unit (GVA 587 A01) 71 67 66 73 102 108

2. GUSP (KYA 924 D01) 04 03 07 09 03 06

3. Total Failures 75 70 73 82 105 114

4. Population (SR) 158 196 240 302 370 450

5. FRPCPY (EQPT) 47.46 35.7 30.4 27.24 28.37 25.33

6. Population (Cards) 2528 3136 3840 4832 5920 7200

7. FRPCPY (CARDS) 2.97 2.23 1.9 1.7 1.77 1.58

Table-2: failures of GU and GUSP

SN Name of Card Type of Card Slot Name

No. Of Failures

2003-04

2004-05

2005-06

2006-07

2007-08

2008-09

1 Power Supply KUB921A01 AB/CD slot 2 2 3 0 5 05

2 Diagnostic computer PPB624A01 U slot 3 1 8 4 9 14

3 Single routine board ARB705B01 E slot 0 2 2 4 1 07

4 Single board computer PPB622B01 G/N/S slot 8 7 10 8 10 24

5 Analog I/O board UAB514B33 F slot 0 0 0 1 0 0

6 Display computer (DDA) PPB908A01 HI slot 1 5 10 8 9 11

7 Digital I/O board URB512D15 J/L/O/Q slot 4 (16%)

3 (13%)

9 (20%)

12 (22%)

29 (41%)

52 (35.86)

8 Bus administrator PPB626B01 T slot 3 0 1 4 3 08

9 Multiple redundant bus coupler UFB660A01 W slot 0 0 0 7 3 12

10 Train bus administrator PPA425B01 YZ slot 2 0 0 5 1 10

11 Rack Rack 0 0 1 0 0 00

12 Unknown 1 4 0 0 0 02

13 Total 25 24 45 53 70 145

14 Population (VCU) 158 196 240 302 370 450

15 FRPCPY(EQPT) 16% 13% 19% 17.6% 19% 32.22%


17 FRPCPY (CARDS) 0.96% 0.78% 1.15%

1.06% 1.2% 1.95%

Table-3: Failures of cards of VCU

22

SN Name of Card Type of Card

Slot Name

No. of failures

2003-04

2004-05

2005-06

2006-07

2007-08

2008-09

1 Controller board PPB471A02 CD slot 6 6 10 8 3 18

2

Chopper Controller/GG/WRE Controller

RDB472A01 F slot 3 0 2 0 5 08

3

Inver Controller/Aux. Interface

UAB476A01 G slot 2 0 0 0 1 04

4 Power Supply KUC153A01 3 (15%)

18 (62%) 9 (31%)

23 (70%)

36 (68%)

39 (50%)

5 Rack 6 4 8 2 8 08

6 Total 20 29 29 33 53 78

7 Population (BUR) 237 294 360 451 546 675

8 FRPCPY(EQPT) 8.5% 10% 8% 7.3% 9.71% 11.56%


10 FRPCPY(CARDS) 1.94% 1.67 % 1.33 % 1.2 % 1.62 1.93%

Table-4: failures of cards of BUR

23

Annex-II

SN Name of PCB Type of card

Slot Name

AJNI GMO GZB LGD Total

06-07

07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

1. NS/AS Controller

PPA988B02 MN/IJ slot

39 41 22 4 6 12 6 7 15 - 1 26 49 55 75

2. Gate Unit GVA 587 A01

SR 13 10 7 53 79 89 7 3 2 - 10 10 73 102 108

3. Digital I/O board URB512D15 J/L/O/Q slot

5 13 9 2 10 7 4 3 12 - 3 24 12 29 52

4. Power Supply KUC153A01 I slot 8 15 15 13 11 12 2 6 3 - 0 9 23 36 39

5. Signal Conditioning Board

UAB630A36/91/93

A/B/C slot of SR

7 11 7 1 3 9 1 4 10 - 3 4 9 21 30

6. GTO optical pulse card

AFB635B08 12/34 slot

7 15 9 0 0 3 0 0 2 - 3 5 7 18 19

7. Single board computer

PPB622B01 U slot(SR)& G/N/S Slot(VCU)

4 3 3 4 12 9 5 5 18 - 1 5 13 21 35

8. Digital I/O board URB177D15 W slot of SR

4 4 1 2 2 3 0 4 5 - 0 1 6 10 10

9. Power Supply KUA 915B01 XYZ slot of SR

6 6 5 2 3 1 2 4 3 - 1 0 11 14 9

10. Diagnostic computer

PPB624A01 U slot of VCU

1 1 2 3 4 2 0 4 4 - 0 6 4 9 14

11. Display computer (DDA)

PPB908A01 HI/H slot of VCU

2 6 0 6 1 5 0 2 4 - 0 2 8 9 11

12. Total 96 125 80 90 131 152 27 42 78 - 22 92 215 324 402

13. Population (EQPT)

312 420 420 451 455 469 294 301 322 - 119 364 1057

1274

1575

14. FRPCPY (EQPT)

30.7%

29.8%

19% 20% 28.8%

32.4%

9.2%

14% 24.2%

- 18.5%

25.3%

20.3%

25.4%

25.5%

Table5: Shed wise failures of cards

24

SN Name of PCB

Type of card Slot Name

BT/S BT/I BHEL NELCO CGL Total

06-07 07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

06-07

07-08

08-09

1. NS/AS Controller

PPA988B02 MN/IJ slot 8 6 15 38 42 52 3 5 6 0 0 2 - - 0 49 55 75

2. Gate Unit GVA 587 A01 SR 58 85 90 2 6 13 12 9 4 - 2 1 1 0 0 73 102 108

3. Digital I/O board

URB512D15 J/L/O/Q slot

1 5 11 5 10 28 4 9 10 0 0 3 2 5 0 12 29 52

4. Power Supply

KUC153A01 I slot 5 4 5 7 21 23 7 5 9 1 0 2 - - - 23 36 39

5. Signal Conditioning Board

UAB630A36/91/93

A/B/C slot of SR

2 1 15 1 9 9 6 2 4 0 6 2 - - 0 9 21 30

6. GTO optical pulse card

AFB635B08 12/34 slot 2 0 2 0 4 5 5 14 11 0 0 0 - - 1 7 18 19

7. Single board computer

PPB622B01 U slot(SR)& G/N/S Slot(VCU)

9 8 14 2 4 9 2 4 9 0 2 2 0 3 1 13 21 35

8. Digital I/O board

URB177D15 W slot of SR

1 3 3 1 2 2 1 3 3 2 2 2 - - 0 6 10 10

9. Power Supply

KUA 915B01 XYZ slot of SR

1 3 3 0 3 1 8 5 4 0 3 1 - - 0 11 14 9

10. Diagnostic computer

PPB624A01 U slot of VCU

0 5 5 1 0 2 0 2 7 0 0 0 0 2 0 4 9 14

11. Display computer (DDA)

PPB908A01 HI/H slot of VCU

5 1 8 0 0 3 2 7 0 0 0 0 1 1 0 8 9 11

12. Total 92 121 171 57 101 147 50 62 67 3 15 15 4 11 2 215 324 402

13. Population (EQPT)

245 245 245 480 515 584 210 357 479 88 103 92 45 45 55 1057 1274 1575

14. FRPCPY (EQPT)

37.5 %

49.4 %

69.8 %

11.9 %

19.6%

25.2%

23.8%

17.4%

14%

3.4%

14.6%

16.3%

8.9%

24.4%

3.6%

20.3%

25.4%

25.5%

Table-6: Make wise failures of cards

25

Annex-III For BTIL:

• 33 microfarad, 25V SMD capacitor, position No. C161 & C167, used in PPB622/624/626/908 cards (table-7).

Parameter Units Existing make Proposed make

Nichicon: UWT1E330MCR1GB Nichicon: PCJ1C330MCL1GS

Type Chip type Non solid Electrolytic Conductive polymer solid Aluminium electrolytic

Temp range deg C -55 to +105 deg C -55 to +105 deg C

Tan delta Nil 0.16 (max) at 120 Hz 20 deg C 0.12 (max) at 120 Hz 20 deg C

Leakage current uA 0.01 CV or 3uA after 2 min (0.01 x 33 x 25 = 8.25 uA)

105 uA

Load Life Hrs 1000 at 105 deg C 2000 at 105 deg C

Ripple current mA (rms) 48 at 100 kHz 2070 at 100 kHz

Table-7: Use of better rated capacitor

• 3900 microfarad, 35 volt capacitors, position no. C215 to C239 used in GVA 587A01 (table-8).


Nichicon:

UPL1E392MPH6

Jianghai:

EC R 1E LH 392 MLL 75 1835

Temp range deg C -55 to +105 deg C -55 to +105 deg C

Size mm 18 (D) x 35.5 (L) x 7.5 (P) 18 (D) x 35.5 (L) x 7.5 (P)

Tan delta Nil 0.14 (max) at 120 Hz 20 deg.C 0.14 (max) at 120 Hz 20 deg.C

Leakage current µA 0.03 CV or 4uA after 1 min. 0.02 CV or 3uA after 2 min.

Load life Hrs 5000 at 105 deg. C 12000 at 105 deg. C

Ripple current (at 105 deg C)

mA(rms) 2690 at 10k to 200kHz 2740 at 100kHz


• 1000 microfarad, 35 Volt capacitor, position No.C39-40/C48-49 used in AFB635 and position No. C215-230 used in XV B175 B32 (table-9).

C161 & C167

26


Nichicon: UPM1V102MHD6 Jiangha:EC R 1V LH 102 M LL 75 1620

Temp range deg C -55 to +105 deg C -55 to 105 deg C

Size mm 16 (D) x 20 (L) 16 (D) x 20 (L)

Tan delta Nil 0.12 (max) at 120 Hz 20 deg.C 0.12 (max) at 120 Hz 20 deg.C

Leakage current µA 0.03 CV or 5uF after 1 min. 0.03 CV re 3uA after 2 min.

Load life Hrs 5000 at 105 deg. C 12000 at 105 deg. C

Ripple current mA(rms) 1770 at 100kHz 1730 at 100kHz


For BHEL:

• 22MF/25 V, ABB REF: - HETT402382P181 (For PPB908A01, PPB622B01, URB177D15 & PPB624B01) (table-10)

Parameter Existing make Proposed make

Type no. ECEVIEV220LP 35JGV22MS6.3X6.1 Make MATSUSHITA RUBYCON Tolerance 20% 20%

Impedance 4.5 Ω 2-3 Ω Ripple 84mA 55mA

Dissipation 0.14 0.14 Life time 1000 hr(-40 to85 °C 2000hr (105 °C)


• 1000MF/35 V, ABB REF: - 3BHC510007R213 (For KUB921A01) (table-11)


Type no. EEUFA1B102B 35YXG1000M-CA12.5X25

Make MATSUSHITA RUBYCON Tolerance 20% 20%

Impedance .034Ω .025 Ω Ripple 1945mA 2230mA Dissipation 0.12 0.12

Life time 5000hr(105 °C) 6000hr(105 °C) Table-11: Use of better rated capacitor

C39-40/C48-49

27

• 10MF/50 V, ABB REF: - HETT402382P0259 (For KUB921A0 URB177D15,

URB512D15) (table-12)


Type no. ECEVIHV100LP 50JGV10M-6.3X6.1 Make MATSUSHITA RUBYCON Tolerance 20% 20%

Impedance 4.5 Ω 2-3 Ω Ripple 45.5mA 35mA



• 4.7MF/50 V, ABB REF: - HETT402382P0257 (For PPB908A01,

PPB622B01,PPB626B01&PPB624B01) (table-13)


• 1MF/50 V, ABB REF: - HETT402382P0253 (For PPB908A01,

PPB622B01,PPB626B01 &PPB624B01) (table-14)


Type no. ECEVIHV010LR 50JGV1M-4X6.1

Make MATSUSHITA RUBYCON Tolerance 20% 20% Impedance 16.5 Ω 2-3 Ω

Ripple 13.7mA 8mA Dissipation 0.12 0.12

Life time 1000 hr(-40 to85 °C) 2000hr (105 °C)


• 33MF/25 V, ABB REF: - HETT402382P0182

(PPB908A01,PPB622B01,PPB626B01 &PPB624B01) (table-15)


Type no. ECEVIEV330LP 25JGV33M-6.3X6.1 Make MATSUSHITA RUBYCON

Tolerance 20% 20% Impedance 4.5 Ω 2-4 Ω

Ripple 84mA 65mA Dissipation 0.14 0.16 Life time 1000 hr(-40 to85 °C) 2000hr (105 °C)



Type no. ECEVIHV4R7L(R) 50JGV4R7M-5X6.1 Make MATSUSHITA RUBYCON

Tolerance 20% 20% Impedance 4.5 Ω 2-3 Ω

Ripple 29.9mA 19mA Dissipation 0.12 0.12 Life time 1000 hr(-40 to85 °C 2000hr (105 °C)

28

• 100MF/160 V, ABB REF: - 3BHC510003R0048 (KUB921A01) (table-16)


Type no. ECEA2CGE101B 160YXF100M-CA16X25


Impedance -- 3-4 Ω Ripple 330mA 950mA Dissipation 0.15 0.12

Life time 2000 hr(105 °C) 5000hr (105 °C)


• 1000MF/25 V, ABB REF: - 3BHC510007R0110 (KUB921A01) (table-17)


Type no. EEUFA1E102(B) 25YXG-1000M-CA12.5X20


Impedance .038 Ω 2-3 Ω Ripple 1655mA 1900mA

Dissipation 0.14 0.14 Life time 5000 hr(105 °C) 6000hr (105 °C)


• 4.7MF/16 V, ABB REF: - ETT402382P0103

(URB177D15,URB512D15,PPB908A01) (table-18)


Type no. ECEV1CV470LP 16JGV47M-6.3X6.1 Make MATSUSHITA RUBYCON

Tolerance 20% 20% Impedance 4.5 Ω 2-4 Ω Ripple 91mA 70mA



29

Annex-IV

SN Speed Location WAG9

Loco No. 31114 (Cab1 working and all six ventilators

open)

WAG9 Loco No.31118 (Cab1 working and two middle

ventilators closed)

WAP7 Loco No.30232 (Cab1 working

and all six ventilators open)

WAP5 Loco No.30009 (Cab2 working

and all four ventilators open)

1 40 Ventilator 1/ CAB-1

6.3 Upward 5.4 Upward Not recorded upto 100 kmph

Not recorded upto 100 kmph

Ventilator 2/CAB-1

7.2 Upward 5.5 Upward

Ventilator Centre 2.2 Upward -

Ventilator Centre 4.4 Upward - Ventilator 1/CAB-

2 4.0 Upward 6.2 Upward

Ventilator 2/CAB-2


2 60 Ventilator 1/CAB-1


Ventilator 2/CAB-1


Ventilator Centre 0.0 Upward - Ventilator Centre 4.1 Upward -

Ventilator 1/CAB-2


Ventilator 2/CAB-2



9.8 Upward

Ventilator 2/CAB-1

10.1 Upward

Ventilator Centre 4.0 Upward

Ventilator Centre 1.5 downward Ventilator 1/CAB-

2 0.2 downward

Ventilator 2/CAB-2

0.6 downward



Ventilator 2/CAB-1


Ventilator Centre 3.8 Upward Not available Ventilator Centre 2.5 downward Not available Ventilator 1/CAB-

2 1.8 downward 1.5 Upward

Ventilator 2/CAB-2

2.0 downward 1.5 Upward


Not recorded Not recorded 16.2 upward 8.7 upward

Ventilator 2/CAB-1

15.3 upward 8.1 upward

Ventilator Centre 6.3 upward - Ventilator Centre 2.7 downward -

Ventilator 1/CAB-2

4.5 downward 16.6 upward

Ventilator 2/CAB-2

4.2 downward 15.7 upward

Table-19: Air velocity at ventilators at different speeds

Reliability of Electronic Cards of Three Phase Locomotives · 2019-10-17 · numbers are provided....

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