Report 2

CERTIFICATE

This is to certify that the project report entitled ‘Types of Relays used in Diesel Locomotives, ECP, OWS, maintainence & Testing’ is being submitted by, in partial fulfillment of project based training for Bachelor of Technology (B.Tech.), in Diesel Locomotive Works, Lucknow from 8th June 2015 to 7th July 2015 i.e., within the duration of four weeks, is a record of bonafide work carried out by him under my guidance and supervision.

Date: (S.K. Vajpayee)

Place: Lucknow SSE, Diesel Locomotive Works,

Charbagh, Lucknow.

ACKNOWLEDGEMENT

“An engineer with theoretical knowledge is not a complete engineer. Practical knowledge is very important for an engineer to develop and apply engineering skill”.

I express my sincere thanks and gratitude to Sri SAH Rizvi Ex-Principal & Sri Sandeep Mukherjee Principal BTC/CB/LKO who has given me privilege to undergo this industrial training at Northern Railway, LOCO WORKSHOP, CHARBAGH, LUCKNOW.

I also extend my heartiest gratitude to Sri S.K. Vajpayee SSE/LOCOSHOP for his creative guidance & valuable suggestion while undergoing this training.

The help and cooperation extended by the staff of SSE, Mr. A.C. Dwivedi, Mr. Javed and other coordinating staff members of Charbagh, Lucknow is fully acknowledged. Words are not enough of thanks for their help and guidance.

Last but not the least I extend my sincere thanks to Dr. Manish Gaur Head Training & Placement Cell, I.E.T. Lucknow for providing me with the opportunity to undergo training in such a reputed organization.

Submitted By:

Sudhanshu Singh, B .TECH. (Electrical Engg.),

Roll No. - 1205220044, I.E.T., Sitapur Road, Lucknow – 21, (U.P.).

2

PREFACE

Project work is an integrated part of ELECTRICAL Engineering program. This emphasizes on the job exposure to real life management situations and to develop simultaneously the ability to relate studies to the real world. This also helps to gain insight into corporate culture and in developing decision abilities.

We undertook our project work in Institute of Engineering & Technology. We worked on ‘Types of Relays used in Diesel Locomotives’.

We were assigned project training at Lucknow Diesel Locomotive workshop for four weeks.

We gained valuable experience and knowledge during the training. This project report consists of our findings and after tabulation of collected data and finally recommendation was put forward. This will be very helpful for us in upcoming days.

3

INDEX

Sr.No. Contents Page No.

1. Introduction to Indian Railways 5

2. Diesel Locomotive Works, Charbagh, Lucknow 6-9

3. DEMU Section 10

4. Reverser 11-12

5. Engine Temperature Switch 12-15

6. Power Contactor 15-16

7. Project 17

8. What is a Relay? 17

9. History of Relay 17

10. Basic Design & Operation 18-19

11. Items of Relay Section for Overhauling 20-21

12. Types of Relays: Latching Relay 22-23

13. General Purpose Relay 23

14. Ground Relay 24

15. Wheel Slip Relay 24-25

16. Maintenance 25

17. Inspection 26

18. Testing 26-27

19. Testing Precautions 27

20. Conclusion 28

4

INTRODUCTION TO INDIAN RAILWAYS

Indian Railways is the state-owned railway company of India. It comes under the Ministry of Railways. Indian Railways has one of the largest and busiest rail networks in the world, transporting over 18 million passengers and more than 2 million tonnes of freight daily. Its revenue is Rs.107.66 billion. It is the world's largest commercial employer, with more than 1.4 million employees. It operates rail transport on 6,909 stations over a total route length of more than 63,327 kilometers(39,350 miles).The fleet of Indian railway includes over 200,000 (freight) wagons, 50,000 coaches and 8,000 locomotives. It also owns locomotive and coach production facilities. It was founded in 1853 under the East India Company.

Indian Railways is administered by the Railway Board. Indian Railways is divided into 16 zones. Each zone railway is made up of a certain number of divisions. There are a total of sixty-seven divisions. It also operates the Kolkata metro. There are six manufacturing plants of the Indian Railways. The total length of track used by Indian Railways is about 108,805 km while the total route length of the network is 63,465 km. About 40% of the total track kilometer is electrified & almost all electrified sections use 25,000 V AC. Indian railways uses four rail track gauges

Indian Railways operates about 9,000 passenger trains and transports 18 million passengers daily .Indian Railways makes 70% of its revenues and most of its profits from the freight sector, and uses these profits to cross-subsidies the loss-making passenger sector. The Rajdhani Express and Shatabdi Express are the fastest trains of India.

5

DIESEL LOCOMOTIVE SHED

CHARBAGH, LUCKNOW

Fig-(1): LUCKNOW DIESEL SHED

Diesel locomotive shed is an industrial-technical setup, where repair and maintenance works of diesel locomotives is carried out, so as to keep the loco working properly. It contributes to increase the operational life of diesel locomotives and tries to minimize the line failures. The technical manpower of a shed also increases the efficiency of the loco and remedies the failures of loco.

The shed consists of the infrastructure to berth, dismantle, repair and test the loco and subsystems. The shed working is heavily based

6

on the manual methods of doing the maintenance job and very less automation processes are used in sheds, especially in India.

The diesel shed usually has:-

Berths and platforms for loco maintenance. Pits for under frame maintenance Heavy lift cranes and lifting jacks Fuel storage and lube oil storage, water treatment plant

and testing labs etc. Sub-assembly overhauling and repairing sections Machine shop and welding facilities.

DIESEL SHED, CHARBAGH, LUCKNOW of NORTHERN RAILWAY is located in LUCKNOW. The shed was established on 22nd April 1857 under Oudh & Rohilkhand Railways for overhauling of steam locomotives. Post independence this workshop came under Northern Railway. It was initially planned to home 75 locomotives. The shed cater the needs of Northern railway. The activities in course of time have changed from POH of steam locomotives to now POH/IOH/ SR of Diesel locomotives (WDM2B, WDM2A, WDM2C, WDP1, WDP2, WDP3, WDG2, WDM3 & WDG3), Electric locomotives (WAM4, WAG5,& WAG7), DMU’s, Rail Buses as well as SPART/ SPARME. Other major activities done in the shop include IOH of coaches, reclamation of CO-CO bogies, Axles Boxes of WDM2 diesel locomotives, traction motors, equalizing beams etc. are continuing. CBW is ISO-9000 certified. Recently, CBW modified a DTC for working in train set with a WDP1 at the other end. This is successfully running in MB division of Northern Railway.

7

This shed mainly provides locomotive to run the mail, goods and passenger services. No doubt the reliability, safety through preventive and predictive maintenance is high priority of the shed. To meet out the quality standard shed has taken various steps and obtaining of the ISO-9001-2000& ISO 14001 OHSAS CERTIFICATION is among of them. The Diesel Shed is equipped with modern machines and plant required for Maintenance of Diesel Locomotives and has an attached store depot. To provide pollution free atmosphere, Diesel Shed has constructed Effluent Treatment Plant.

(a) OVER VIEW

Inception 22nd April1857

Present Holding 147 Locomotives

19 WDM2

37 WDM3A

08 WDM3D

11 WDG3A

46 WDP1

26 WDP3A

Accreditation ISO-9001-2000 & ISO 14001

Covered area of shed 10858 SQ. MTR

Total Area of shed 1,10,000 SQ. MTR

Staff strength Sanction – 1357

On roll - 1201

Berthing capacity 17 locomotives

8

(b) CLASSIFICATION

1. Standard “Gauge” designations and dimensions:-

W = Broad gauge (1.67 m) Y = Medium gauge ( 1 m) Z = Narrow gauge ( 0.762 m) N = Narrow gauge ( 0.610 m)

2. “ Type of Traction” designations:-

D = Diesel-electric traction C = DC traction A = AC traction CA=Dual power AC/DC traction

3. The “ type of load” or “Service” designations:-

M= Mixed service P = Passenger G= Goods S = Shunting

4. “ Horse power ” designations from June 2002 (except WDP-1 & WDM-2

LOCOS) ‘ 3 ’ For 3000 horsepower ‘ 4 ’ For 4000 horsepower ‘ 5 ’ For 5000 horsepower ‘ A ’ For extra 100 horsepower ‘B’ For extra 200 horsepower and so on

.

Hence ‘WDM-3A’ indicates a broad gauge loco with diesel-electric traction. It is for mixed services and has 3100 horsepower.

9

D.E.M.U. SECTION

Fig-(2): A DEMU Train

Fig-(3): DEMU Workshop

10

The various parts of a DEMU train that are repaired, maintained and tested in this section include the following:

Reverser Engine Temperature Switch Power Contactor Relays

• Reverser A Reverser is used to reverse the direction of train by reversing the direction of power supplied to it. In DEMU, the reverser used is of 2-contact type having 4 units on each contact. It is operated either manually (by a long handle) or by supplying air pressure.

Fig.-(4): Top view of a Reverser

11

Testing of Reverser:

The testing of Reverser is done by a test known as ‘Paper Test’. In this test, a thin strip of Butter Paper is inserted between the fixed and moving contacts. As the moving contacts strike the fixed contacts, the butter paper is tried to pull up.If the butter paper slides out easily, then contacts are not perfect and they need disassembling and reassembling till the contacts become perfect and the paper does not slide out.

• Engine Temperature Switch (E.T.S.)

Engine Temperature Switch consists of a temperature sensor which is used to measure the temperature of the engine coolant of an internal combustion engine. The readings from this sensor are then fed back to the Engine control unit (ECU), which uses this data to adjust the fuel

12

injection and ignition timing. On some vehicles the sensor may also be used to switch on the electric cooling fan. The data may also be used to provide readings for a coolant temperature gauge on the dashboard.

Fig-(5): An E.T.S.

Fig-(6): Inside an E.T.S.

13

Operation:

The ECU sends out a regulated reference voltage (typically 9 volts) to the coolant temperature sensor. The voltage drop across the sensor will change according to the temperature because its resistance changes. The ECU is then able to calculate the temperature of the engine, and then (with inputs from other engine sensors) uses lookup tables to carry out adjustments to the engine actuators, i.e. change the fuel injection or ignition timing. This is necessary because in order to run smoothly, a cold engine requires different timing and fuel mixture than an engine at operating temperature.

Fig-(7): Test Bench of an E.T.S.

14

• Power Contactor

A contactor is an electrically controlled switch used for switching an electrical power circuit, similar to a relay except with higher current ratings. A contactor is controlled by a circuit which has a much lower power level than the switched circuit. Contactors are used to control electric motors, lighting, heating, capacitor banks, thermal evaporators, and other electrical loads. A contactor has three components. The contacts are the current carrying part of the contactor. This includes power contacts, auxiliary contacts, and contact springs. The electromagnet (or "coil") provides the driving force to close the contacts. The enclosure is a frame housing the contact and the electromagnet. Enclosures are made of insulating materials like Bakelite, Nylon 6, and thermosetting plastics to protect and insulate the contacts and to provide some measure of protection against personnel touching the contacts. Open-frame contactors may have a further enclosure to protect against dust, oil, explosion, hazards and bad weather.

15

Fig-(8): Power Contactors fitted in a Diesel Engine

16

Project Title: Types of relay used in Diesel locomotives, ECP, OWS, maintenance and testing. What is a relay? A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current. The heart of a relay is an electromagnet (a coil of wire that becomes a temporary magnet when electricity flows through it). You can think of a relay as a kind of electric lever: switch it on with a tiny current and it switches on ("leverages") another appliance using a much bigger current. Why is that useful? As the name suggests, many sensors are incredibly sensitive pieces of electronic equipment and produce only small electric currents. But often we need them to drive bigger pieces of apparatus that use bigger currents. Relays bridge the gap, making it possible for small currents to activate larger ones. That means relays can work either as switches (turning things on and off) or as amplifiers (converting small currents into larger ones).

History Relays were invented in 1835 by American electromagnetism pioneer Joseph Henry; in a demonstration at the College of New Jersey, Henry used a small electromagnet to switch a larger one on and off, and speculated that relays could be used to control electrical machines over very long distances.

17

Fig-(9): An EM Relay

Basic design and operation A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core, an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts (there are two in the relay pictured). The armature is hinged to the yoke and mechanically linked to one or more sets of moving contacts. It is held in place by a spring so that when the relay is de-energized there is an air gap in the magnetic circuit. In this condition, one of the two sets of contacts in the relay pictured is closed, and the other set is open. Other relays may have more or fewer sets of contacts depending on their function. The relay in the picture also has a wire connecting the armature to the yoke. This ensures continuity of the circuit between the moving contacts on the

18

armature, and the circuit track on the printed circuit board (PCB) via the yoke, which is soldered to the PCB. When an electric current is passed through the coil it generates a magnetic field that activates the armature and the consequent movement of the movable contact either makes or breaks (depending upon construction) a connection with a fixed contact. If the set of contacts was closed when the relay was de-energized, then the movement opens the contacts and breaks the connection, and vice versa if the contacts were open. When the current to the coil is switched off, the armature is returned by a force, approximately half as strong as the magnetic force, to its relaxed position. Usually this force is provided by a spring, but gravity is also used commonly in industrial motor starters. Most relays are manufactured to operate quickly. In a low-voltage application this reduces noise; in a high voltage or current application it reduces arcing.

Fig-(10): Relay-Constructional Details

19

Items of Relay Section (DSL) for Overhauling

Sr.No. Item 1. G.P. Relay, G.R. Relay, Wheel Slip Relays

2. R1,2 with arc box, CKC with arc box

3. F.P.C. with arc box

4. G.F.C. with arc box

5. F.S.C. with arc box

6. CK1,2,3 with arc box

7. E.P. Contactor with arc box

8. Bell Buzzer

9. PCS (P1,2, PCS1,2, EPG)

10. Load Meter(LM1,2)

11. Electronic water meter indicator sensor unit

12. Low water alarm switch(L.W.S.)

13. LED Flasher Light1,2, Control and lamp unit

14. DC-DC Converter

15. LED Indication Panel

16. Separately Alternator mounted power rectifier

17. Thyrite resistor(G.F.R) Engine temperature control resistor(TCR)

18. Power control ground resistor panel

19. Load ammeter resistor panel

20. Inverse Voltage Suppression Panel (VSP)

21. Miscellaneous item(GROC,CPR,RCD,TB,VSPETC)

20

22. Excitation Panel(EXCP) with card

23. Transition Panel (TRP) with card

24. Voltage Regulator Panel(VRP) with card

25. Stabilizing Panel

26. Load Control Resistor(LCR)

27. Generator/Alternator voltage divider panel(VCD)

28. Oscillator voltage divider resistor panel(OVDP)

29. Alternator field resistor(AFR), Head lamp resistor(HLPR),WSSR

30. Load control resistor, Limit resistor

31. Tacho generator load resistor(TGLR)

32. Breaking unit voltage divider

33. Voltage regulator current limit switch(VRCLS)

34. Load ammeter shunt(LAS), Armature current reactor(ACR)

35. Engine Temperature switch(ETS).

21

Types of Relays

• Latching relay A latching relay (also called “impulse”, “keep”, or “stay” relays) maintains either contact position indefinitely without power applied to the coil. The advantage is that one coil consumes power only for an instant while the relay is being switched, and the relay contacts retain this setting across a power outage. A latching relay allows remote control of building lighting without the hum that may be produced from a continuously (AC) energized coil. In one mechanism, two opposing coils with an over-center spring or permanent magnet hold the contacts in position after the coil is de-energized. A pulse to one coil turns the relay on and a pulse to the opposite coil turns the relay off. This type is widely used where control is from simple switches or single-ended outputs of a control system, and such relays are found in avionics and numerous industrial applications.

Fig-(11): A Latch Relay

22

Another latching type has a remanent core that retains the contacts in the operated position by the remanent magnetism in the core. This type requires a current pulse of opposite polarity to release the contacts. A variation uses a permanent magnet that produces part of the force required to close the contact; the coil supplies sufficient force to move the contact open or closed by aiding or opposing the field of the permanent magnet.A polarity controlled relay needs changeover switches or an H bridge drive circuit to control it. The relay may be less expensive than other types, but this is partly offset by the increased costs in the external circuit.

• General Purpose Relay a) Earth Fault/Ground Fault monitoring of three phase systems b) Microcontroller based design c) SMD technology, Manual Reset d) Input 1A or 5A through CBCT e) Adjustable Earth Fault trip setting f) Adjustable trip delay and ON delay g) 2 co relay output h) Failsafe-Non failsafe selectable

Fig-(12): General Purpose Relay

23

• Ground Relay An electrical relay provided in diesel and electric traction system to protect the equipment against damage from earth and so called “ground”. The result of such a relay operating is usually a shutdown of the electrical drive. It is also some time called an earth fault relay. The Ground Relay as used on a diesel electric locomotive provides a number of important features. It was originally applied to furnish flashover protection but has become useful in connection with other functions so that it now provides protection on a diesel electric locomotive for: 1) Armature grounds in either the main generators or traction motor 2) Accidental power circuit grounds 3) High resistance creepage grounds, such as those caused by

moisture and dirt 4) Flashover protection for generators, motors and contactors 5) Ground protection during dynamic braking 6) Ground protection during engine starting.

Fig-(13): Ground Relay

• Wheel Slip Relay A Wheel Slip relay has four terminals. Two of those are use in series operation and another two are used in parallel operation. At the starting time out of six traction motor each two are connected in series and those all three constructions are connected in parallel with a resistor. In between one pair of motors the wheel slip relay is connected in the equi-potential position.

24

Fig-(14): Wheel Slip Relay

Maintenance Periodic relay testing is, first and foremost, preventive maintenance. Thus, procedures and records should be designed with preventive maintenance as the guide. The tests themselves will reveal catastrophic failures which would have prevented the relay from performing when called upon to operate, while properly maintained records will reveal any trends which could lead to such failures. The tests to be performed during routine maintenance are, of course, determined by the type of relay to be tested. However, the following tests should be included for all electromechanical relays. Also mentioned are some preventive measures which may be indicated by the results of such tests.

25

Inspection Before the relay cover is removed, a visual check of the cover can reveal valuable information as well as prevent possible trouble. First, of course, excessive dust, dirt or metallic material deposited on the cover should be noted and removed. Removing such material will prevent it from entering the relay when the cover is removed. The presence of such deposits may call attention to the need for some form of air filtering at the station. "Fogging" of the cover glass should be noted and removed when the cover has been re-moved. Such fogging is, in most cases, a normal condition due to volatile materials being driven out of coils and insulating materials and, as such, merely requires its removal from the glass. However, if the fogging appears excessive, further investigation is indicated. Since most relays are designed to operate in ambient temperatures not exceeding 104 °F, a check of the ambient temperature would be in order. Testing A high quality relay test set and tools are important to te st protective relays in an accurate and repeatable manner. Troubleshooting of microprocessor-based relays may also require specialized equipment, a laptop computer, communication cables, and software. Check manufacturer’s recommendations for necessary tools and equipment. If not available at the facility, most test equipment and tools can be borrowed from 86-68450, phone 303-445-2305. Microprocessor relay testing can be automated. These relays can be tested with computer-based software that communicates with both the relay and test set. It is preferable to test relays using automated testing procedures to reduce the time required and increase reliability and repeatability of tests being performed. However, it is critical that the person responsible for relay testing be totally familiar with the relays, external protective circuits, and all test procedures. All automated testing procedures must be validated by a qualified person before using them to test relays. Due to the critical nature of protective relays and enormous

26

prohibitive cost of a failure-to-trip or false trip, only a thoroughly trained, experienced person should perform and/or oversee these tests. Testing Precautions To preclude inadvertent trips, before starting any relay test with protected equipment in service, testing personnel must be familiar with relays and associated circuits. When test blocks are used, ensure that removing or inserting plugs will not open a CT secondary. Opening a secondary with the primary energized will result in high voltage which can destroy the CT or other equipment, be dangerous to personnel, and/or cause an inadvertent trip. If test blocks are not available, before the relay CT circuit is opened, CTs must be shorted by the shorting blocks provided by the manufacturer or by shorting switches. Before removing any relay from service, be very cautious; the unit may need to shut down for relay testing, or the unit may have redundant protection and can continue to operate during testing. In any case, do not allow the unit to operate without any relay protection while testing.

27

Conclusion

Training opportunities and facilities provided to us were adequate and helpful. Each and every department of this organization has given us full cooperation. All the instructors journey in the reputed organization.

During my training period, I have gained adequate and valuable knowledge regarding various machineries and instruments used in DLW(Lucknow). I hope that whatever valuable knowledge and experiences I have gained during this period, will be useful and helpful in my future professional career.

28