1 Loco Section.

1.1 Loco Commercial

The main objective of this department is interaction with customer. It brings out tender

and notices and also responds to them. It bags the contracts to manufacture locos.

After delivery it further takes care and interrogates of faults and failures as well and takes

the appropriate action to solve the problem.

Its function can be broadly classified as:

1.1.1 Tendering

1. Tender:

Requirement of customer comprises of the following:

a) Technical specification / requirement

b) Estimated cost of project / equipment

c) Estimated time of completion of project

d) Other information

2. Type of tenders:

Broadly classified as:

a) Open tender-published in news dailies, open for all

LOCOMOTIVE MANUFACTURING

b) Limited tender issued to limited parties

c) Single party tender-issued to single party on propriety basis

3. Enquiry:

On receipt of tender forms formal enquiries are issued to:

a) Engineering department-for technical acceptance

b) Production planning and control-for delivery period

c) Central dispatch cell-for mode of transportation and transportation charge

4. Offer:

If tender is feasible as obtained from reports of other departments offer is submitted

to customer.

5. P.O /Contract Agreement:

On the opening of technical bid the commercial bid of technically qualified tender

is opened and order is placed on lowest value tender followed by negotiations if

required.

1.1.2 Contract Execution:

1) Issue of work orders: on receipt of purchase order internal work orders are

issued by commercial department for execution of work.

2) Type of work orders: 1) Technical, 2) Financial, 3) Shipping

3) Monitoring: To maintain the key dates of the contract internal meetings with

the concerned departments are held on regular basis to monitor the progress.

4) Payment collection: To collect the payment from the customer.

5) Contract closing: After the dispatch and completion of all the aforesaid tasks

the contract is formally closed by commercial department.

1.1.3 After sales service:

1) Within warranty period free of cost service and replacement of material if

required

2) Beyond warranty period on chargeable basis

1.2 Locomotive manufacturing

A locomotive can be broadly classified as:

a) Superstructure

b) Under frame

c) Bogie

1.2.1 FABRICATION

This shop does not come under Loco Unit but manufactures all the basis parts

necessary fore locomotive manufacturing like Shell, Traction Transformer etc.

PARTS MADE IN THE SHOP

STRUCTURE

SHELL

UNDERFRAME SUPERSTRUCTURE

CABIN SIDEWALL ROOF

BOGIE FRAME

To manufacture the structure following Machines are used in fabrication shop.

BUTLER Milling Machine: It is a PLANO Milling machine with multiple

cutting tools. It is used for milling operation. Its milling head is universal which

does angular movement for chamfering.

Bending Machine: It performs bending operation on thick metallic sheets of

thickness up to 32mm and of length up to 3200mm approx. tonnage of capacity is

500 tones stroke of machine (height up to which tool is lifted) is 15mm. shut

height from top is 250. max pressure which can be applied is 140kg/cm2

Rolling Machine: It contains one power generating roller, below two are

driving rollers. This is used to roll the sheet.

Roller arm drilling machine: it has a fixed bed. If job cannot be fixed on the

bed it can be rotated to work directly on the job. Its movement is controlled

hydraulically in vertical direction.

Hydraulic press Machine or flattening Machine: It flattens the thick metal

sheets in the shop. It has a max. capacity of 100 tones.

CNC Flame Cutting Machine: It is used to cut various shapes on thick sheets

of metal. This is done by suitable program feed in machine.

Sample program: For creating the following shape

G91G21M04 Y-15X15 Y15X1422X15 Y-15Y-275X-15 Y-15X-1422X-15 Y15Y275M30

G91G21M04 X75

G02 I-75M03 X-75X172Y229.5M04 X-60G02 X50 Y-50 J-50Y-359G02X-50 Y-50 I-50X-244 G02X-50 Y50 J50Y359G02X50 Y50 I50X244M03 M30

Welding Process in Fabrication Shop

Welding is a process of joining together of two metal pieces to produce essentially a single piece of metal.

Basic Arc welding Process1. Shielded Metal Arc Welding(SMAW)2. Gas Tungsten Arc Welding(GTAW)3. Gas Metal Arc Welding(GMAW)4. Flux Cored Arc Welding(FCAW)5. Submerged Arc Welding(SAW)

Two types of Welding used in BHEL Jhansi.

GMAW

Submerged Arc Welding(SAW) • Submerged Arc Welding is a arc welding process where weld is produced by

heating with an electric arc between a bare metal electrode and the work.• The welding zone is shielded by a blanket of granular fusible material on the

work.• Pressure is not used .• Filler metal is obtained from the electrode wire.

ELECTRODES• Electrodes classification as per AWS A 5.1.

1. The prefix E refers to Arc welding electrodes.2. The first two digit indicate minimum tensile strength in psi, Ex: E60XX indicate minimum tensile strength 60,000 psi.3. Second last digit indicates the welding position. 1- All position. 2- Flat position and horizontal fillets.4. The last two digit together indicate the welding position giving coating type current and polarity.

POLARITY

• When the power source is DC the work is connected with positive pole of the machine, it is called Straight Polarity or DCEN(DC Electrode Negative).

• When the work is connected with negative pole of machine it is called Reverse Polarity or DCEP(DC Electrode Positive)

• The Positive Pole generates two third of heat produce.

Common Electrode used in BHEL, Jhansi• E6013 suitable for all welding position can be used with AC and DC negative.• E7018 low hydrogen electrode suitable for all welding position can be used with

AC and DC(+)• E7024 iron powder electrode suitable for flat position can be used DC and AC

both.• E309 for welding mild steel and stainless steel.• E308 for welding stainless steel.

WELDING CHECKS & TESTS• LPT/DPT ( Liquid/dye penetrant test)• MCD / MPI ( Magnetic Crack Detection/ Magnetic particle detection)• UT ( Ultrasound Testing)• RT ( Radiographic test )• Colour Wave length(m) frequency(Hz)• Red 6.22-7.8 x 10¯7 4.82- 3.84 x 10¹4• Orange5.97-6.22 x 5.03-4.82• Yellow5.77-5.99 5.20-5.03• Green 4.92-5.77 6.10-5.20• Blue 4.55-4.92 6.59-6.10• Violet 3.90-4.55 7.69-6.59

LIGHT OF VISIBLE SPECTRUM Wavelength 7.8 x 10¯7 m down to 3.8 x 10¯7 m and frequency 4x 10¹4 Hz upto 8 x 10¹4HzX-ray Wavelength 10¯9 m down to 6x 10¯12 m and frequency between 3 x 10¹4 Hz and 5x 10¹9 Hz

1.2.2 Locomotive Manufacturing Unit

Here is the locomotive manufacturing unit .It has been divided in two shops:

1) Bogie shop

Step by step process carried out in Bogie shop

A.1. Machining of axle

Axle is prepared in bogie shop out of thick cylindrical raw material.

Facing and drilling operation is done on the axle. Turning operation is done on the axle to get the required

diameter, by CNC machine. Grinding operation is done on the axle to make the surface

smooth.

2. Preparation of collar and wheelThe collar and wheel are machined to get the desired accuracy. Collar contains a small hole inside which helps in releasing of oil. It is provided across the gears so that it doesn’t move on axle and forms a firm grip.

3. After machining these parts are assembled on pressing machine. The collar, gear, wheel are pressed on the axle via pressing machine.

4. Tube is fitted on the axle and traction motor is assembled on it. Tube supports the traction motor and keeps it stationary while axle is rotating. The gear and pinion (gear of traction motor) are meshed together (the teeth’s are in ratio 64:16 respectively).

5. Axle box is assembled. It has tapered bearing system.6. After the assembly is complete following test is performed as

per the specification:Wheel Testing: In this process the testing of the assembly of traction motor and wheel (with gears and axle box) on axle is done. This test is called traction motor run test. In this test servo-57 or ENCLO-68 oil is used. It ensures clean commutater.

Specification: In axle caps of TM-4906 and

TM-4605 AZ Traction motor supply-

Voltage 30-40 V DC

Current 70-90 AmpsDuration 2hrs

Backlash test: Any backlash if occurred is recorded and any abnormality like bearing noise is also noted. Backlash limits 0.3-0.8mm.

B.1. Bogie frame is prepared by achieving desired accuracy. Accuracy is achieved by machining it through CNC machine (COOPER machine).2. After final machining bogie fitting is done. Bogie fitting includes following steps:

Liner mounting is done. It is done so that the shell of the bogie can be mounted at this place. The shell structure is pivoted at this place, and liner provides a smooth joint.

Pneumatic brake system is installed. a) Bush brake system is assembled.b) Brake rigging is done.

Wheel axle system is mounted. Suspension arrangement is done which includes mounting

of springs and linkages. Beam mounting is carried out by mounting two equalizer

beams. These beams maintain the alignment of the train by transmitting the suspension motion equally.

Bogie trail load is applied for coupling of Axle with Bogie by tightening of Horn Stay to the Bogie. By applying load the vertical gap between the axle box and padstle reduces and thus the gap can also be maintained. Horn stay provides a support to the axle mounted in the padestle, so that if frame assembly is lifted the Wheel Axle arrangement does not run out.

Rubber is mounted on the frame which is connected to the Traction motors for giving a vibration absorbing support caused due to the suspension of Wheel and Axle system.

After bogie frame is ready it is send to the assembly shop.

2. Assembly shop:

The shell is received from fabrication shop.

Dismantling of roof Transformer marking drilling

Main reservoir &Aux. reservoir mtg.

Battery box mtg.

After cooler mtg.

SL-30 1st,2nd mtg.

Cattle guard mounting at both end.

Pivot mtg.

AC-2 panel mtg.

MVMT 1st mtg.

Roof sub. Assy.

a) Roof line & Panto insulater mtg.

b) Lightening Arrester

c) Earthing on roof.

Compressor (MCP)-1,2,3 mounting.

Baby Compressor mtg. with its oil tray.

AC transformer mtg

Power cable termination

Painting

Chequred plate in cabin-1&2

Cable laying

General Inspection

Testing

1.2.3 TESTING

Testing is carried out after all the assembly is complete. Following steps are performed in testing:

1. HV & IR (High Voltage and Insulation Resistance) Test: In this testing the insulation of the cabling is tested. Whether there is any leakage of current and its resistance fits the required limit.

2. Sequence Test: This is to check whether the wiring is done accordance with the drawing or not and supply circuit is working properly.

3. Under Catenary Test: 100V supply is provided through battery to baby compressor (8 kg/cm2) then Pantograph is lifted. VCB (Vacuum Circuit Breaker) is closed so that the supply gets transferred. Supply goes to the Rectifier, SL etc. and the circuit is thus tested completely.

4. Auxillary Run Test: MVMT (for cooling of motors), MVRH (cooling of circulated oil), MVSL (cooling of smoothening reactor), MVSI (cooling of rectifier), MVMP (cooling of motors) run test.

5. Pneumatic Test: This is to check the working of brake system.6. Traction Motor Test: To check the direction of rotation of traction motor.7. Rain Test.

8 Long Run Test: Final Bogie is tested by running 4-5 km in nearby station and DBR test is performed during the run.

1.2.4 Various machines employed in the shop:

1) HOESC –pressing machine –wheel, axle, collar, and gears are pressed together on this machine. Pressing limit (95 – 132 tones)

2) Cooper machine: wheel turning CNC machine.

Specification

Travel along x-axis – 1000mm

Travel along z-axis – 3000mm

Swing over bead – 760mm

Spindle nose – 5mm

Spindle power – 20 kw

3) Asquith CNC machine (bogie machining centre): Bogie after being

prepared from fabrication shop comes to bogie shop for machining. In machining

of bogie, various processes like boring drilling, milling, facing etc is done through

ASQUITH CNC MACHINE

Specification of this machine are :-

1. travel in x –axis 8000 mm

2. travel in y- axis 4000 mm

3. travel in z- axis 800 mm

4. spindle dia. - 180 mm

5. spindle power 40kw

6. auto tool changer 40 tools

4) Hydraulic arm drilling machine

5) Radial arm drilling machine

6) Turret lathe:

Specification:

Swing over saddle- 596mm (max)

Swing over cross

Slide-317mm

Flange to turret

Face – 1500mm

7) Axle drilling machine

8) Centre drilling and facing machine:

Specification:

Work holder – 160*3000 HID

Stock removal – 5.5mm

Gang drilling – 3no UNC 98mm PCD/100mm PCD

Motor power – 10.5 – 5.5 HP

9) Axle turning machine

10) Churchill machine tool: CNC vertical milling m/c

Specification:

1. Travel in x-axis – 1200mm

2. Travel in y-axis – 600mm

3. Travel in z-axis – 400mm

4. Spindle dia – 180mm

5. Spindle nose – ISO 50

6. Spindle power - 30 kw

7. System – SINUMARIL 80Omm

11) Hydraulic Pipe Bending Machine: This machine is in Assembly Sop and it

is used to bend pipe of various diameter at various angles.

Specification:

Max. capacity 65mm OD*6mm thick ferrous tube

Max. bend radius - 300mm

Length over mandrel - 6mtr

Hyd. Tank capacity - 200 ltr

Total H.P- 100

1.2.5 Types and product ranges:

a) Electric Locomotives :WAG-9,WAG-7,WAG-5,WCAM-2,WCAM-3,WCAG-1

b) Diesel Electric Shunting Locomotives :350 hp,450 hp,700 hp(TPP),1150

hp(SPP),1350 hp(SPP),1400 hp(SPP),2600 hp(SPP)

c) New Products :

1. OHE (Recording and Testing car)

2. UTV (Utility vehicle)

3. RRV (Rail cum Road vehicle)

4. DETV (Diesel Electric Tower car)

5. BPRV (Battery powered road vehicle)

6. BCM (Ballast cleaning machine)

7. Metro Rake-Kolkata Metro Railways

8.200 T Well wagon for BHEL Haridwar

This section deals with manufacturing of locomotives.

The main parts of the locomotive are

Under frame: The frame on which a locomotive is built

Super structure: The body of locomotive is called superstructure or Shell and

is made of sheet of Mild steel

DC motor

Alternator

Compressor

Flower

Static Rectifier-MSR

Static Converter-SC

Exchanger

Bogie-The wheel arrangement of a loco is called a bogie. A bogie essentially

contains

1-wheel axle arrangement

2-Suspension

3-Brake rigging

Traction transformer: It is fixed on under frame and gets supply from

an overhead line by equipment called pantograph. The type of pantograph depends

on supply. This transformer steps down voltage and is fitted with a tap changer.

Different taps are taken from it for operating different equipment. One tap is taken

and is rectified into DC using MSR and is fed to the DC motor.

Railways has two types of power supplies – 25 KV, 1 Phase, 50 Hz AC

-1500 V DC

An AC/DC loco is able to work on both of these supplies. For e.g. WCAM-3.

1.3 LOCOMOTIVE PRODUCTION (LMP)

There are two products

Alternating Current Locomotive (ac Loco)

WAG-7

AC./D.C. Loco

o WCAM-2P

o WCAM-3

W-broad gauge A-running in AC mode

C-running in DC mode G-hauling goods train

P-hauling passenger train M-hauling passenger& goods train

Diesel Electric Locomotive Shunting (DESL)

350 HP

700 HP

o Single Power Pack (SPP): One 700 HP m/c is made as a single

unit. It is a meter gauge locomotive.

o Twin Power Pack (TPP): 2 350HP m/cs are combined in 1

engine & can be operated individually or in combination

depending on the load.

450 HP

1400 HP

1150 HP

1350 HP

2600 HP

1150 HP and 1350 HP DESL s are non-standard locomotives and are modified versions

of 1400 HP DESL based on requirement of customer.

Under mention are the new non-conventional products designed and developed for Indian

Railways based on their requirement.

OHE (Overhead electric) recording and testing cars

UTV(Utility vehicle )

RRV(Rail cum road vehicle)

DETV( Diesel electric tower car)

BPRV(Battery power road vehicle)

BCM(Blast cleaning machine)

200 T Well wagon for BHEL Haridwar

Metro Rake-Kolkata Metro Railways

1.4 Locomotive Engineering (LME)

It forms a link between locomotive commercial department and manufacturing unit. It

take the technical specification of the job from commercial department and prepare the

drawing of the job required taking all the constraints into consideration. Various

software’s such as AutoCAD, Catia, Ansys are used, however manual drawings is also

required sometimes.

Presently they are working on the designing of WAG-9. WAG-9 is upgraded model of

WAG-7. It has additional features such as Air Conditioned driver cabin etc.

1.5 Locomotive Planning (LMP)It looks after that how a certain project is to be executed so that it turns out smoothly. The

various functions performed by it includes customer enquiry, receipt of order, issue of

work order from commercial department, issue of manufacturing information from

Engineering, product specification and routing sheet, indenting of items etc.

1.6 STORES :There are three sections in store:

Control Receiving Section

Custody Section

Scrap Disposal Section

2. ELECTRIC LOCOMOTIVE WAG-72.1 INTRODUCTION

The BHEL Jhansi performs its own tests to check the quality of the job undertaken

besides that railway takes utmost care to keep the quality check in control by establishing

its own RDSO (Research Designs & Standards Organisation) unit in the BHEL

compound to regularly monitor the proceedings of the order. The RDSO is headquartered

at Lucknow. Now let us have a look on the work undertaken by the locomotive section:

SL. NO. TYPE OF

PRODUCTS

PRODUCTION

YEAR1. 350 HP DIESEL ELECTRIC SHUNTING

LOCOMOTIVE

1985-86

2.

700 HP T.P.P. DIESEL ELECTRIC

SHUNTING LOCOMOTIVE

1986-87

3. 700 HP S.P.P. DIESEL ELECTRIC

SHUNTING LOCOMOTIVE

1987-88

4. A.C. ELECTRIC LOCOMOTIVE WAG-5

HB

1988-89

5. 450 HP DIESEL ELECTRIC SHUNTING

LOCOMOTIVE

1990-91

6. 1150 HP DIESEL ELECTRIC

SHUNTING LOCOMOTIVE

1991-92

7. 2600 HP DIESEL ELECTRIC

SHUNTING LOCOMOTIVE

1992-93

8. 1350 HP DIESEL ELECTRIC

SHUNTING LOCOMOTIVE

1992-93

9. 1400 HP DIESEL ELECTRIC

SHUNTING LOCOMOTIVE

1993-94

10. A.C./D.C. ELECTRIC LOCOMOTIVE

WCAM-2

1994-95

11. A.C./D.C. ELECTRIC LOCOMOTIVE

WCAM-3

1995-96

12. A.C./D.C. ELECTRIC LOCOMOTIVE

WCAG-1

1998-99

13. 200MT WELL WAGON 1998-99

14. O.H.E. RECORDING TEST CAR 1998-99

15. 800 HP DIESEL HYDRAULIC

SHUNTING LOCOMOTIVE

1999-2000

16. KOLKATA METRO 2000-01

17. UTILITY VEHICLE (UTV) 2002-03

18. RAIL CUM ROAD VEHICLE 2002-03

19. DIESEL ELECTRIC TOWER CAR 2003-04

20. B.P.R.V. 2003-04

21. BATTERY LOCOMOTIVE 2004-05

22. SYNCHROLIFT HOIST ASSEMBLY 2004-05

23. D.T.S. 2005-06

24. B.C.M. 2008-09

25. WELL WAGON-280T 2008-09

26. ACEMV RAKE 2008-09

27. WAG-7 2008-09-10

There was no order from the Indian Railways during the period 1999-2007. New orders

were received of WAG-7 for 50 locomotives in December 2007 and tender for 150

numbers WAG-7 is still under negotiation. The designs are provided by the CLW

(Chittranjan Locomotive Works) and specifications provided by the RDSO are

implemented by the BHEL.

2.2 TECHNICAL PARAMETERS

1. Power Supply 22.5 KVA AX, 50 Hz

2. Continuous rated power 5000 Hp at rail

3. Max. Service Speed 100 km/hr

4. Axle Load 20.5 t

5. No. Of Axles 6

6. Gauge 1676 mm

7. Stating Tractive Effort 44.0 t

8. Haulage Capacity 4830 t@ 86 km/hr

9. Balancing speed on level 86 km/hr

10. Gear Ratio 16/65

11. Control System Tap changer with microprocessor based fault diagnostic system

2.3 EQUIPMENTS AT A GLANCE

Figure 1.1 BLOCK DIAGRAM OF ENGINE ROOM LAYOUT

Cab 1 COMPRESSOR

MVMT BLOWER: Cooling of traction motors.

BA-1 PANEL: Speeding control through shunt resistance.

TRIPLATE PNEUMATIC CONSOLE

RSI-1 {RECTIFIER}

DYNAMIC BRAKE RESISTANCE (DBR)

SL-30 {SMOOTHING REACTOR}: Removes pulses from DC signal.

TRANSFORMER

SMGR (TAP CHANGER)

SL-30{SECOND}:

ATFEX TRANSFORMER

BA-3 PANEL

BA-2 PANEL

RSI-2

RC-DAMPING

STATIC CONVERTER: Converts single phase current to 3 phase.

MVMT BLOWER-2

BABY COMPRESSOR

CAB 2The above flowchart clearly gives us a handy look at the equipments used in the

locomotive WAG-7. The coding of the locomotives has been already discussed in the

second chapter of this report but even then I am breaking code for the present

locomotive.

W- BROAD GAUGE A- RUNNING IN AC MODE G- HAULING GOODS TRAIN

So, this locomotive is basically made for hauling goods train or we can say its freight

carrier.

In this part, we had a glimpse of all the major equipments used in WAG-7 but being an

Electrical & Electronics student in the coming sections my main emphasis would be

on the electrical equipments being used in the locomotive WAG-7.

2.4 WAG-7 TENDER SPECIFICATION

The electrical equipment should generally include:

1) Components for collection of power from the overhead system

2) Converter set comprising of main transformer, rectifier, smoothening reactors and

voltage control device.

3) Auxiliary machine i.e. various rotary and static machines required for offered

traction equipments.

4) Traction motor, reverser, main line contactor and field weakening devices, etc.

5) Rheostat braking equipment

6) Low voltage control equipment, protective devices/relays, etc.

7) Sanding control apparatus

8) Signaling and indicating lamp and lighting equipment

Now in the sections to follow we would be seeing that what the electrical equipments

that are mounted are, what is the purpose of that equipment, and its advantages.

2.5 PANTOGRAPH

The pantograph is the collector used to slide along the contact wire as has been explained

in section 3.6.3.1. It has a conducting strip which is pressed against the contact wire by

springs. The collector strips are usually of steel with grease lubrication, or of carbon, in

which case no lubrication is needed. Function of the pantograph is to maintain as constant

a pressure as possible between the collector strip and contact wire and to prevent any

vertical oscillation of the collector strip; as these will produce arcing due to braking of

electric contact. When the pantograph is not in use, it is maintained in lower position with

the help of stiff springs. The collector strip is raised by compressed air when it is to be

used.

Figure 4.2 PANTOGRAPH

As per the specifications, the WAG-7 locomotive shall be equipped with two pantographs having the metallised carbon strips. Normally, the trailing end pantograph will be used but a selector switch should be provided on the driver’s desk so that either or both of the pantographs can be raised. The raising up or down of the pantograph while in motion should not cause any disturbance in the OHE. 2.6 MAIN CIRCUIT BREAKER

An electro pneumatically operated single bottle vacuum circuit breaker is mounted on the

roof of the locomotive to connect the transformer to 25 KV AC overhead line through

the pantograph and to clear any fault in traction power circuit. The breaker should be

operational via a switch located in the driver’s cab. The circuit breaker should have a

rupturing capacity of 400MVA and a continuous rating of 1000Amps at 25 KV. The

suitable interlocks are provided for tripping the circuit breaker in case the air pressure

becomes low to a value at which the raised pantograph leaves the contact wire.

2.7 LIGHTENING ARRESTOR

A gapless lightening arrestor of proven design similar to those working in three phase

locos is provided for protection against the line voltage transients caused by lightening or

system switching.

2.8 MAIN TRANSFORMER

As supply lines are to be laid all along the track, with adequate spacing, the economy

dictates use of minimum number of such lines. Therefore, single phase supply is used.

The current enters locomotive through the collector. This is where the use of transformer

arises. The current from the collector flows through the primary of a step down

transformer and returns to supply earth through locomotive wheels and one of the rails on

which the locomotive travels, thus avoiding need for a second conductor. Main secondary

windings of the transformer feed the power modulator, which in turn powers the driving

motors. The auxiliary secondary windings of the transformer feed power for other needs

of the train such as lighting, fans, air conditioning etc.

Now, in WAG-7 the main transformer is of oil immersed type. The oil is forced

circulated through the windings by an electric pump and cooled in a radiator by a blower

set. The transformer has a variable auto transformer winding incorporating various taps

connected to the tap changer, the nominal voltage being 22.5 kV and maximum 27.5 kV.

The transformer also has a fixed ratio transformer, the primary winding of which is

connected to the auto transformer tap changer having a variable voltage from 0 to 22 kV.

This transformer has two separate secondary windings. The continuous rating of rectified

current is 2x2700Amps and apparent power for traction on primary and the designed

power of secondary are same that is 5400kVA.

2.9 TAP CHANGER

A transformer tap is a connection point along a transformer winding that allows a certain

number of turns to be selected. By this means, a transformer with a variable turn ratio is

produced, enabling voltage regulation of the output. The tap selection is made via a tap

changer mechanism.

If only one tap changer is required, tap points are usually made on the high

voltage, or low current, side of the winding in order to minimize the current handling

requirements of the contacts. However, a transformer may include a tap changer on each

winding if there are advantages to doing so. For example, in power distribution networks,

a large transformer may have an off-load tap changer on the primary winding and an on-

load tap changer on the secondary winding. To minimize the number of windings and

thus reduce the physical size of a transformer, a 'reversing' winding may be used, which

is a portion of the main winding able to be connected in its opposite direction and thus

oppose the voltage. Insulation requirements place the tap points at the low voltage end of

the winding. This is near the star point in a star connected winding. In delta connected

windings, the tapping is usually at the center of the winding. In an autotransformer, the

taps are usually made between the series and common windings, or as a series 'buck-

boost' section of the common winding.

With an on load tap-changer the transformer voltage can be varied in steps by

adding or subtracting turns. For this purpose a transformer is furnished with a tapped

winding and these taps are connected to terminals on the tap-changer. The tap-changer

provides two basic functions, first to “select” a transformer tapping connection in an

open-circuit condition, the second is to “divert” or “transfer” power to that selected

tapping without interrupting the through current.

In WAG-7 the tap changer is on load type oil immersed with oil circulating pump and

filter. It has 32 running taps controlled by an electro pneumatic servo motor.

2.10 RECTIFIER

The locomotive is provided with two sets of air-cooled silicon rectifier connected in

Graetz Bridge. Each of these rectifiers are supplied by a separate secondary of the main

transformer.

2.11 TRACTION MOTOR

Traction motor refers to an electric motor providing the primary rotational torque of a machine, usually for conversion into linear motion i.e. traction.

Traction motors are used in electrically powered rail vehicles such as Electric multiple

units and Electric locomotives, other electric vehicles such as electric milk floats,

elevators and conveyors as well as vehicles with electrical transmission systems such as

diesel-electric and electric hybrid vehicles. Additionally the electric motors in other

products such as the main motor in washing machines are described as traction motors.

Figure 4.3 TRACTION MOTORBefore the mid-20th century, a single large motor was often used to drive multiple

driving wheels through connecting rods that were very similar to those used on steam

locomotives. It is now standard practice to provide one traction motor driving each axle

through a gear drive.

Usually, the traction motor is simply suspended between the truck (bogie) frame and the

driven axle; this is referred to as a "nose-suspended traction motor". The problem with

such an arrangement is that a portion of the motor's weight is unsprung, increasing forces

on the track.

In WAG-7 the traction motor used is of series DC pulsating current type. The

armature is vacuum pressure impregnated solvent less resin. The motor fulfils the

following parameters broadly:

Mounting: Axle hung nose suspended

Rating: One hour: 750V, 960A, 870RPM, 670 kW

Continuous: 750V, 900A, 895RPM, 630kW

Weak field: 40%

Maximum permissible Ripple 28%

at continuous current of 900A

Starting current: 1350A for 2 minutes

Short time rating: 1200A for 10 minutes

2.12 RHEOSTATIC BRAKING

Dynamic braking is the use of the electric traction motors of a railroad vehicle as

generators when slowing the vehicle. It is termed rheostatic if the generated electrical

power is dissipated as heat in brake grid resistors and regenerative if the power is

returned to the supply line. Dynamic braking lowers the wear of friction braking

components and additionally regeneration can also lower energy consumption.

During braking the motor fields are connected across either the main traction

generator (Diesel-electric loco) or the supply (Electric locomotive) and the motor

armatures are connected across either the brake grids or supply line. The rolling

locomotive wheels turn the motor armatures, and if the motor fields are now excited, the

motors will act as generators. For a given direction of travel, current flow through the

motor armatures during braking will be opposite to that during motoring. Therefore, the

motor exerts torque in a direction that is opposite from the rolling direction. Braking

effort is proportional to the product of the magnetic strength of the field windings, times

that of the armature windings.

The locomotive WAG-7 is equipped with rheostatic braking arrangement

capable of braking effort of around 20T over a speed range of 25 to 50 km/h. In the event

of failure of the electric brake brakes on the train the air brake on the locomotive will be

applied automatically. Braking effort regulation are obtained by adjustments of the

traction motor excitation. The field of all the motors are connected in series and fed by

one of the two silicon rectifier bridge connected by means of an intermediate transformer

to one of the two secondary windings of the transformer. The control of the excitation is

provided by the tap changer. The dynamic braking resistance is forced cool by AC motor

blower set (AC MVRF). In case of emergency brake application by the driver, the electric

brake, if applied will be automatically cut off.

2.13 BATTERY

Batteries of adequate capacity are provided on the locomotive to feed the equipment for

three hours starting with a half charged battery when the locomotives are coupled in

multiple. The battery can be of lead acid type or latest with PPCP containers.

2.14 CONTROL EQUIPMENT & SAFETY DEVICES

The LED flashers light are provided in the locomotive. The microprocessor based control

and fault diagnostic systems are there which can even indicate the availability of OHE

power supply through capacitive coupling.

The safety devices include a new feature in the locomotives manufacturing. The

Vigilance Control Device (VCD) has been installed on WAG-7. The driver has to

acknowledge to periodic vigilance check by pressing a push button. In case the driver is

not vigilant with the first step then the device will flash an indication. If even now, the

driver does not respond then an audio-visual warning will be played and in case of no

response automatically the emergency brakes will be applied and the whole loco has to be

started all again.

2.15 POWERING OF SINGLE PHASE LOAD

This part is not associated with the manufacturing but is an important part of traction

system and I believe this report would be incomplete without discussing this part. The

locomotive power ratings can be as high as 6000 HP. The WAG-7 has a power rating of

5000 HP and powering such a large single phase load can lead to large unbalance in the

supply system which is always three phase. Due to this the track supply is divided into

sections which are electrically isolated from each other, and substations supplying these

sections are connected to different phases of the three phase supply. Though the

unbalance is reduced, its magnitude still remains large. If the three phase supply system

capacity is much larger than the power drawn by the locomotive, then this unbalance will

not significantly affect the three phase supply system. Therefore, it is essential that the

main source of traction supply should be sufficiently large.

Figure4.4 SCHEMATIC DIAGRAM OF TRACTION SUBSTATION

2.16 PNEUMATIC BRAKING SYSTEM

In the air brake's simplest form, called the straight air system, compressed air pushes on a

piston in a cylinder. The piston is connected through mechanical linkage to brake

shoes that can rub on the train wheels, using the resulting friction to slow the train. The

mechanical linkage can become quite elaborate, as it evenly distributes force from one

pressurized air cylinder to 8 or 12 wheels.

The pressurized air comes from an air compressor in the locomotive and is sent from car

to car by a train line made up of pipes beneath each car and hoses between cars. The

principal problem with the straight air braking system is that any separation between

hoses and pipes causes loss of air pressure and hence the loss of the force applying the

brakes.

Ballast Cleaning Machine

Traction

Sub Statio

n

R,Y

R,Y

LOCORAIL

OHE25 KV AC Single phase

INTRODUCTION

The Ballast Cleaning Machines offered by BHEL is based on proven on Track Ballast

Cleaning system of M/s. MTH PRAHA a.s., Czech Republic with all major components

of working unit imported from MTH. The Power unit made by BHEL as per basic design

and specification of foreign MTH PRAHA as. The fabricated frame work (steel

structure) for working unit (SCV 602 IN) is manufactured at BHEL works and the

assembly of the entire unit is done under technical supervision of the experts from MTH

PRAHA.

The machines offered will not only provide trouble free service and durability but will

also pave the way for reliable Track maintenance for Indian Railways.

BCM being manufactured by BHEL Jhansi, Comprises mainly of two parts:

a.) Power Car

b.) Working Unit

Ballast Cleaning Machine

(Power Car)

Power car comprises of one no. KTA 38L Cummins make diesel engine.(1120

hp).

Traction Alternator TA 6301AZ

Twin Impeller Blower 10000cfm

Aux. generator AG2513

IR make Compressor model 15T.

Screw Coupler with hook.

Roof mounted radiator with fan hydraulically driven.

Dynavane filter.