Safety is first

ELECTRIC LOCOMOTIVE SHED

E co Railways

Vishakhapatnam

Certificate

This is to certify that the project report entitled ‘study of electric traction motors and locomotive transformers’ is being submitted by, in partial fulfillment of project based training, in electric locomotive shed, Vishakhapatnam from 28th dec2010 to 7th jan2011 I.e., within the duration of two weeks, is a record of bonafide work carried out by him under my guidance and supervision.

Signature of the guide:

Name:

Designation:

Department:

ABSTRACT

In this project we studied about different types of locomotives and

their operation in different sections and studied about traction motors,

transformers, relay circuits, rectifiers, alternator (ARNO) during the

testing and servicing of respective blocks

Index

Contents1. Introductions

2. Classification of locomotives

3. Main blocks of locomotives

4. Types of traction motors used in locos

5. Auxiliary motors

6. Transformer

7. Alternator

8. Braking system

9. Earthling and bonding

10. Insulators

IntroductionElectric loco shed Vishakhapatnam:This is the shed that hosts a large number of wAG5 type electric locomotives whose primary job is to haul long iron ore freight trains from the iron mines around kirandul to the vizag port. The trains are usually attached with three WAG5 locomotives, each with a power more than 4000hp. These locos haul the ore through some of the most treacherous terrains in India crossing mountains and forests. The loco shed also hosts all the WAG6 type (Hitachi and ABB) locomotives available with Indian railways.

Classification of locomotives:

In India locomotives are classifies according to their track gauge, motive power, the work they are suited for and their power or model number. The class name includes this information about the locomotive. It comprises 4 or 5 letters. The first letter denotes the track gauge. The second letter denotes their motive power (diesel or electric) and the third denotes the kind of traffic for which they are suited (goods, passenger, mixed or shunting).

The forth letter used to denotes locomotive model number. However, from 2002 anew classification scheme has been adopted. Under this system, for new diesel locomotives, the forth letter will denotes their horsepower range. A locomotive have a fifth letter is its name which generally denotes a technical variant or subclass or subtype. This fifth letter indicates some insulator variation in the basic model or series, perhaps different motors or a different manufacturer.

Track gauge

Broad gauge is the most predominant gauge used by the Indian railway. The total length of track used by Indian railways is about 111559 km while the total route length of the network is 63465km.about 28% of the route –kilometer and 40%of the total track kilometer is electrified. Indian railways use three gauges, the broad gauge which is wider than the 1435mm, standard

gauge: the meter gauge and the narrow gauge 762 mm

The first letter (gauge)

W = Broad Gauge Y = Meter Gauge Z = Narrow Gauge (2' 6") N = Narrow Gauge (2')

The second letter (motive power)

D = Diesel C = DC traction A = AC traction CA = Dual-power AC/DC traction B = Battery electric(rare)

The third letter (job type)

M = Mixed Traffic P = Passenger G = Goods S = Shunting L = Light Duty (Light Passenger?) (no longer in use) U = Multiple Unit (EMU / DEMU)

Electric traction voltages used for electric traction in India

Voltages used are 1.5kV DC and 25kV AC for mainline trains.

Calcutta had an overhead 3kV DC system

The 1.5kV DC overhead system (negative earth, positive catenary) is used around Bombay

In preparation for this, BHEL has been retrofitting some Alstom EMUs with AC drives to allow them to operate with both DC and AC traction as the system conversion proceeds.

The 25kV AC system with overhead supply from a catenary is used throughout the rest of the country. The WCAM series of locomotives are designed to operate with both DC and AC traction as they move towards or away from the Bombay DC section.

The new [2003] AC-DC EMU rakes used in Mumbai are also designed to operate with both DC and AC traction as the Bombay area switches over to the 25kV AC system.

The Calcutta Metro uses 750V DC traction with a third-rail mechanism for delivering the electricity to the EMUs.

The Calcutta trams use 550V DC with an overhead catenary system with underground return conductors. The catenary is at a negative potential.

The Delhi Metro uses 25kV AC overhead traction with a catenary system on the ground-level and elevated routes, and uses a rather unusual 'rigid catenary' or overhead power rail in the underground tunnel sections (Line 2).

Blocks of general locomotives:

Pantograph

For collecting power from 25 kV ac contact wire pantographs are mounted on the roof of the traction vehicles.. AM 12 pantograph of Faively design has been adopted by Indian Railways for 25 kV ac electric locomotives. These pantographs are provided with steel strips for current collection. The raising and lowering of the pantograph is by means of a pneumatically operated servo motor. This pantograph is a single pan design having two o-springs mounted on it. For keeping the pantograph in the lowered condition, main springs have been used. The suspension of pan is on plungers.

Circuit Breaker

Since inception of 25 kV ac traction system, Air Blast Circuit Breakers were used on electric locomotives. These breakers are designed for isolation of power to the traction vehicle in the event of faults. The life of the main contact on this account is also limited. This breaker also requires substantial amount of dry air for each switching operation.

Vacuum circuit breaker:

Vacuum Circuit Breakers were introduced on electric locomotives on Indian Railways. The VCB is a simplified design has a simplified control block and self - contained interrupting medium that is vacuum to stop the locomotive

Transformer

Power to the traction vehicles is available at 25 kV ac single phase from the contact wire. In order to step down the voltage as well as to control the same for feeding to the traction motors, the traction power transformers are provided on the traction vehicles.

These transformers generally have a primary winding, a regulating winding, traction secondary windings and auxiliary windings. The regulating winding is designed for choosing appropriate voltage for the traction motors. The auxiliary winding is required for feeding the

auxiliary motors on the locomotive.

In order to increase the horse power of the locomotives, the traction transformers have been up rate. The up ratings have been achieved by using increased copper section of the conductor used, improved insulation scheme and in certain cases adoption of aluminum foil wound construction for minimizing the losses.

With the introduction of thyristorised converters, the design of the traction transformer has undergone simplification with the deletion of regulating winding. The transformer for thyristorised converter becomes a two limb construction and traction secondary winding split into 4 windings for two step sequence control.

The traction transformer necessarily has to have forced oil circulation and forced air cooling. For this purpose oil pump, oil cooler and blower form an integral part of the traction transformer.

Tap Changer:

The Tap changer is provided on 25 kV (HT) regulating winding of locomotive transformer for controlling the voltage input to main transformer. The Tap Changer operates with the help of elaborate mechanism using an air driven Servo Motor (SMGR) and a bevel gear arrangement. Through precision adjustment and provision of transition resistance (RGR) it is ensured that there is no break of load current in-side the selector (GR) which is oil filled and the load current is broken by load switches known as CGR1, CGR2 and CGR3.

Traction Motor:

Our Indian railways in olden day’s compound motors are used for traction but now a day’s using DC series motors as traction motors for running locomotives. While comparing with AC motors these DC motors are efficient and high starting torque. The speed control of DC motor is very easy but in AC three phase induction motor it is difficult. For every locomotive there are 6 DC traction motors in which all six are connected in parallel. The speed of the traction motor is controlled by tap changer circuit with 32 notches.

These traction motors are manufactured by chitranjan locomotive works. There are many types of traction motors which are used according to the load, speed, power and etc.

The some of the models which are used by east coast railways are

TAO 659: this type of motor is used in WAM4, WAP1, WAP3, WAG5, WCAM2 Electric locomotive models. This light weight motor is suitable for 4000 HP, 25 kV AC CO`- CO` type of bogies. These motors are also suitable for dual voltage locomotives such as 25 kV AC / 1500 V DC. This axle hung nose suspended traction motor is designed with robust construction and can be used with different gear-ratios for diversified applications.

HS15250:

This type of motor is started in 1993. The traction motor is designed for 4000 HP and 5000 HP, 25KV AC CO`- CO` electric locomotives type WAG5, WAP2 and WAG7 being manufactured at Chittaranjan Locomotive Works (CLW). Also the same is being used on AC / DC and DC 5000 HP / 4700 HP locomotives. This axle hung nose suspended traction motor is designed with robust construction and can be used with different gears for diversified applications.

Manufactured by : Chitranjan locomotive works

model TAO 659Continuous output 585kw

Volts 750vStarting current 1350ACurrent(cont) 840A

Speed 1060rpmMax service speed 2500rpm

Field Series field( 6p)with inter poles

Insulation Class HNo of poles Main 6,

commutating 6Horse power 4000watts

Cooling system Air blower

L3M450: it is a special machine which is imported from Japan and Sweden. This type of motor is used in locomotives WAG 6A only. Generally these are high power compared to WAG 5.

All WAG-6 locos were at Waltair (Vishakhapatnam) and have generally been used for ore freights and material trains on the Kirandul-Kottavalasa line. Six bogie-mounted separately excited DC traction motors are used, and speed control is via the manipulation of the phase angle by a thyristor converter and a separately powered field coil. This loco is controlled with a thyristor used in locomotive

Manufactured by

Hitachi

Continuous output

785kw

Volts 850vCurrent 960A

Speed 970 rpmInsulation Class HField Series field with

commutating poles

Manufactured by Chitranjan locomotive works

Model HS15250AContinuous output 630kwVolts 750vStarting current 1350ACurrent (cont) 900ASpeed 895rpmMax service speed 2150rpmField Series field with

commutating polesInsulation Class cNo of poles Main poles 6,

commutating poles 6

HS15256

oru

Arno Converter

Arno Converter is a special duty machine for conversion of single phase in-coming supply into 3 phase out- put supply. 3 phase supply is essentially required on most of the electrical locomotives for driving certain auxiliary equipment like blowers and compressors. The function of Arno Converter is to supply 3 phase power required for these auxiliaries. It converts single phase supply from main transformer to 415v three phase supply for auxiliary motors.

Arno Converter of horizontal construction was used in WAG 4x\WAG5x\WAG6x\WAG7x locomotives. Indigenously developed Arno Converter however is of vertical construction. The machine has mechanical construction suitable to withstand the severe vibrations encountered on locomotives.