new loco project
DESCRIPTION
bhel jhasi reportTRANSCRIPT
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.