VOCATIONAL TRAINING

REPORTEASTERN RAILWAY

SEALDAH DIVISION

Submitted by :

Souptik Mukhopadhyay

5th Semester

Dept. of Electrical Engineering

I.I.E.S.T,Shibpur

ACKNOWLEDGEMENTS

I, the undersigned student of Electrical Engineering department of I.I.E.S.T,Shibpur(formerly known as Bengal Engineering and Science University, Shibpur) have completed two weeks training at Eastern Railway (Sealdah Division).

I am very much grateful to the authority of the organization for taking initiative for the vocational training to upgrade my knowledge by placing me at Eastern Railway (Sealdah Division). I owe many thanks to several people who helped and supported me during this training.

I wish to express my gratitude to the officials and other members of Eastern Railway who rendered their help during the period of my training.

I am extremely grateful to the H.R. Department and Electrical Department of Eastern Railway (Sealdah Division).

I express my sincere gratitude to:Mr. Asit Das of Power House/ Substation.Mr. Yadav Roy, Mr. Paltu Ghosh, of AC Coaching and Rajdhani Express Department.Mr. Tiwari Yadav, Mr. Mondal of TL Coaching.

Last but not the least I wish to avail myself of this opportunity to express a sense of gratitude and love to my friends and my beloved parents for their heartiest support, guidance and for everything. With due regards and thanks to everyone involved in this project I conclude this project.

Yours sincerely

Souptik Mukhopadhyay

1. TRAIN LIGHTING

TRAINING PERIOD: 23/06/2014 TO 26/06/2014

INTRODUCTION

Train lighting of a self-generated coach is being discussed here. The generation is done by the under gear equipment i.e. a 3 phase brushless alternator with a Rectifier cum Regulator Unit(RRU)

ALTERNATOR

S P E C I F I C A T I O N O F A L T E R N A T O R :

Connection StarGenerated voltage 97V ACRating 4.5kWNo. Of V grooves 4

The alternator is mounted between two wheels. The V belts are attached in the V grooves on the pulley attached to the shaft and the axis of the wheel.

External Components:

Bogie bracket Suspension pin Cutter pin Split pin Bogie nylon bush Tension rod Bogie bush

Alternator power supply

1. The alternator starts producing voltage when rotor achieves a minimum speed of 350rpm.The alternator does not generate until the train achieves a minimum speed of 22kmph.

2. The output of alternator is provided to RRU at an optimum speed of 38kmph

3. 110 V DC from RRU feeds the whole lighting system of the coach and simultaneously charges the cells used underneath each coach .When the train is at standstill the charged cells provide the lighting..

RECTIFIER CUM REGULATOR UNIT(RRU)

Main features of ERRU with UVC: Fast and reliable switching devices. Alternator identifying facilities and Auto setting of parameters such as output DC voltage, battery

current, load current which in turn increase the life of battery and the alternator itself.

Monitoring real time value of alternator voltage, load current, battery AH (IN), AH(OUT) etc., through interface fitted inside the coach.

Main Components of ERRU : The main components of the ERRU are as follows

Terminal Box Power Unit Universal Voltage Controller (UVC) Static Over Voltage Protection (OVP) Emergency Field Extension with interface High Reliable Components

Hall Effect Sensor. ISOPACK Power Diodes.

Main advantages of ERRU: Control circuit is Modular type design. Auto identification of alternator ratings and indications. Auto setting of parameter of voltage, load current, Battery

current, over voltage, over current and current limiting for all the regulator of 4.5 kW, 18 kW and 25 kW.

UVC is interchangeable with all types of Electronic Regulators from 4.5 kW to 25 kW.

Close regulation of voltage +/- 2 V over the entire range of load and speed to have uniform charging of batteries.

Less voltage and current ripple on Battery Charging current. Controlled Battery charging current to have longer life of

batteries. Rating and Settings :

4.5 kW Regulator: Ratings : Voltage : 124 V Full Load amps : 38 A Speed Range : 550 RPM to 2500 RPM.

Settings : Normal : 124V +/- 0.5 V at 19 Amp. And at 1500 RPM Facility available for setting: 120V,122V & 124V Load Current : 42 Amp (Maximum) Battery charging current: 24 Amp (Max.)

HIGHLY RELIABLE COMPONENTS :

High reliable components are added to minimize the failure in the Electronic Regulator. The working principle of these components are ad mentioned below are explained here under.

Hall Effect Senor.

Isopack Power Diodes.

HALL EFFECT SENSOR :

The Hall sensor is a transformer operating with a balanced magnetic flux principle to measure D.C. – A.C – pulsating current with galvanicinsulation between primary and secondary circuits. The primary current produces a magnetic field, which is detected by a Hall Effect device and, via an electronic amplifier, is immediately balanced by injecting a current into the secondary winding. The secondary current thus injected is the exact replica of the primary current times the turns ratio. This closed loop current sensing is fed into the main circuit to limit the output current and protect the equipment from over current.

ISOPACK POWER DIODES :

These diode modules contain two diodes in a single pack and have a base plate, which is ceramic isolated from the power circuit. They canbe mounted directly on the heat sinks needing no insulation in between. This results in effective heat transfer to the heat sink and thereby reducing temperature of the device. These modules are tested for more than 1.5 kV isolation between live terminals and base place. The ratings of devices are as follows – VRRP : 1800 Volts peak to peak. I (avg) : 350 Amps.

PERIODICAL MAINTENANCE INSTRUCTION FOR ERRU

1. Check all the connections are tight. If found any loose connection,tighten the connection.2. Care must be taken for connecting the terminals in correct polarity.

The reverse connection may cause severe damage in regulator.3. Do not disconnect the connectors from UVC and terminals. If anydisconnection is found, connect the connectors in original position.Do not connect any wrong side and wrong connection will causedamage in regulator.4. Do not keep open the UVC door as well as regulator box andterminal covers. Open door may give chance to enter the dust and metallic things inside and this may cause any short circuit in theregulator.5. In case of fuse blown, is suggested to use proper HRC fuse. Donot tie with wire and this wire-fuse will cause any damage in theregulator.6. Protections are safety for our systems; so do not bypass theprotecting systems lie, OVP and fuse.

BATTERIES

Description of different types of cells:

Lead acid cells demand less maintainence and are less costly.

Type of cells in use for train lighting and coach air-conditioning are :- Capacity of battery in AH Type of coachat 27 Degree C at 10 Hr Rate where generally used120 110 V, BG coaches450 MG AC Coach525 Jan Shatabdi Non - AC coaches800 II AC BG Coaches (Old) (Under-slung type)1100 II AC BG Coaches (new)/AC 3 Tier Coach

PRINCIPLE OF OPERATION : In a charged lead acid cell positive terminal consists of lead peroxide (PbO2) and the negative terminal of spongy lead (Pb). Dilute sulphuric acid (H2SO4 + H2O) serves as electrolyte. The overall reactions inside the cell during discharge and charge are represented most -conveniently by a reversible equation as follows :-

PbO2 + Pb + 2H2SO4 <=> 2PbSO4 + 2H2O

During discharge, the lead peroxide on the positive plates as well as the spongy lead on the negative plates are converted into lead sulphate (PbSO4). In this process, sulphuric acid (H2SO4) is consumed and water (H2O) is formed. Consequently, the specific gravity of the electrolyte falls, the extent of fall being proportional to the ampere-hours taken out. The process at first causes a slow, and then a faster voltage drop, until a permissible lower limit(final discharge voltage) is reached, which depends on the rate of discharge current. The amount of ampere-hours (constant current x time) taken out is called the capacity of the cell at this rate.The chemical process during charge is the reverse of that during discharge. The lead-sulphate on the positive plates is reconverted into lead peroxide and the lead sulphate in the negative plates into spongy lead. Sulphuric acid is formed and the water consumed. The specific gravity of the electrolyte rises. There is at first a slow, later a faster rise of cellvoltage. From 2.4 volts onwards gassing sets in due to a strong decomposition of water into hydrogen and oxygen. Violent gassing is injurious to the plate material. So after reaching this gassing voltage the rate of the charging current must be limited to within safe permissible values.

MAINTENANCE :Hydrometer is used to ascertain the specific gravity of electrolyte in a lead acid cell. The specific gravity is the relative weight or density of the electrolyte as compared with a similar volume of pure water. The specific gravity of a cell should be maintained at the value given by the manufacturer in the fully charged condition. This value for fully charged cells at 27 degree C shall be between 1,210 and 1,220 for cells up to 525 Ah capacity and between 1.245to 1.255 for cells over 525 Ah capacity as per IS:6848.Voltmeter is used for taking the individual voltage of cells and the battery as awhole. This voltmeter shall preferably be of a dry cell operated digital type with a range of D.C. from 0 to 200 V.

GENERAL

The rating assigned to the cell or battery is the capacity expressed in ampere-hours(after correction to 27 degrees C) stated by the manufacturer to be obtainable when the cell or battery is discharged at the 10

Hr. rate to the end voltage of 1.80 V per cell.Train lighting batteries of coaches by the very nature of service conditions cannot be expected to have steady rate of charge/discharge. They are often left to idle for longduration or charged at higher rates. Such strenuous service of these cells therefore calls forsystematic and thorough examination while in service, prompt remedial measures of defects/replacement of cells and quality POH work in Shops to achieve the expected life without any loss of efficiency below 80 %.

Running maintenance of storage batteries falls under four categories :-1. Trip examination,2. Fortnightly examination,3. Quarterly examination,4. Intermediate overhaul.

Replace vent plugs after taking specific gravity and ensure that they are tight."SWITCH ON" lights and fans in each coach and take the voltage readings across the set of 56 cells. "SWITCH OFF" all lights and fans.Tap the floats of each cell and check for correct electrolyte level as indicated in the float stem. Replace missing/defective floats. In case of low level, replenish with pure battery grade water. If any cell needs too much water for replenishing, watch for crack in the cells and also check the voltage on load which should not be less than 1.80 V. In case of anydefect, remove the cell and replace by a spare one preferably of the same make and lug date or a lug date as close to the one already in the coach. Use special containers provided with automatic siphoning device to RDSO drawing No. SKEL 611 for topping up battery grade water. Check tightness of packing and use additional packing if required.Coaches with discharged batteries which show less than 22 V on load should be put on charge at double the normal rate of charges and continued as long as possible till gassing starts or till the specific gravity rises to the fully charged value which should be between 1.210 and 1.220 for the cell up to 525 Ah or as recommended by the manufacturers and which is stenciled on the battery box. Use the battery charging terminals provided in coachesfor charging purposes. Never skin the insulation of cables near end cell connections for this purpose. Check up correct polarity and connect the charging cables. Use a clip-on d. c. ammeter of 0-100 A range to check up the battery charging current. Note down the rate of charging and the number of hours of charge.

Check the specific gravity of Pilot cells and the total voltage of battery on load at the end of charge and record. Keep vent plug tight. Ensure that washer is available for vent plugs. The person in charge of battery maintenance should record all the readings mentioned above in his diary and this information should be transferred to the register maintained for various trains.Check anti-theft rods and provision of nuts both inside and outside the battery box on either side. Replace if found missing. Secure battery box cover finally after all works are completed.

CARRIAGE FAN

GENERAL 400 mm, 300 mm and 200 mm sweep carriage fans are used on Indian Railways in SG, MOG, and EOG coaches where the system voltage could be DC 110 V or AC 110 V. As a passenger amenity item, carriage fans have to be maintained in such working condition as to obtain good air flow and trouble free service for ensuring maximum passenger satisfaction.

SPECIFICATION Railway carriage fans are either of the fixed or swiveling type and conform to specification IS: 6680. Performance requirements of these fans are as follows:

PERFORMANCE DATARequirement D.C. Fan sizes A.C. Fan sizes 400 mm 300 mm 200 mm 400 mm 300 mm 200 mmMinimum Air in m3/min 50 37 20 65 30 14Maximum Electrical Power 35 29 18 60 40 28input in Watts

Maximum Weight in kg. 15 14.5 10 15 14.5 10

CARRIAGE LIGHTING

GENERAL Carriage lighting is provided from :-a. Axle driven generators in conjunction with storage batteries on D.C. 110 V system..b. Diesel generator sets with step down transformers on A.C. 110 V in MOGsystem,c. Diesel generator sets with step down transformers on A.C.110V in E.O.G system.

Ceiling light fittings in I, II&III AC, II Sleeper, postal vans and dining carson DC 110 V sys.: 18 W, 2 ft. long fluorescent lampswith inverters

OVERALL SCHEMATIC DIAGRAM OF POWER DISTRIBUTION FROM ALTERNATOR

2. POWER HOUSE

TRAINING PERIOD: 26/06/2014 TO 30/06/2014

INTRODUCTION

o A substation is a part of an electrical generation, transmission and distribution system. Substations transform voltage from high to low or

reverse or any of several other important functions. Electric power may flow through several substations between generating plant and consumer,and its voltage may change in several steps.

o A substation has a step up transformer increase the voltage while decreasing the current ,while a step down transformer decrease the voltage

while increasing the current for domestic and commercial distribution .The word substation comes from the days before the distribution system became a grid. The first substation were connected to only one power station, where the generators were housed and were subsidiaries of thatPower station.

IN SEALDAH POWER HOUSE the control is divided into two sections.

1. THE LOW TENSION SECTION2. THE HIGH TENSION SECTION

The main components of the power house are

Transformers{300 KVA &500 KVA} Circuit breakers { Air circuit breakers on L.T side & vacuum

circuit breakers on H.T section } Relays { Earth Fault Relay & Over Current Relay } Bus Coupler Hooter / Alarm Isolator {P.F :1 Sub Station }

The components are described in brief from the power house below:-

STEP-DOWN TRANSFORMER

A transformer is a device that transfers electric energy from one circuit to another circuit through inductively coupled conductors---the transformers coil---a varying current in the first or primary winding creates a varying magnetic flux in the transformer core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF) or voltage in the secondary winding. This effect is called mutual induction.

If a load is connected to the secondary, an electric current will flow in the secondary winding and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer ,the induced voltage (Vs) in the secondary winding is proportion to primary voltage (Vp) and is given by the ratio of the number of turns in the secondary(Ns) to the number of turns in primary(Np) as follows-----

Vs/Vp=Ns/Np

By appropriate selection of the ratio of turns, a transformer thus allows an alternating current voltage to be “stepped up” by making Ns greater than Np or “steped down” by making Ns less than Np.

In the vast majority of transformers, the winding are coils wound around a ferromagnetic core, air-core transformers being a notable exception.

IN SEALDAH POWER HOUSE two transformers are used, one 300KVA and another 500KVA.

A spare 300KVA transformer is kept for backup.

Transformer ratings:-

C SERIAL NO: 1581/D7-08MAKER AUTOMATIC ELECTRIC GROUPKVA 500KVAVOLTS AT NO LOAD H.V: 6000V

L.V: 415VAMPERES H.V: 48.11A

L.V: 695.62APHASES H.V: 3

L.V: 3TYPE OF COOLING OIL NATURAL COOLINGFREQUENCY 50C/SIMPEDENCE VOLTS 4.37%VECTOR GROUP REF DY11CORE & WEDGES 1140KGWEIGHT OF OIL 451KGTOTAL WEIGHT 2105KGOIL AMOUNT 530LITRESMAX. TEMP RISE IN OIL 45 DEGREE

500KVA transformer

ALARM/HOOTER SYSTEM(BUCCHOLZ RELAY)

The alarm is employed to the system to indicate the faulty condition. If any fault occurs in the system components the alarm sounds to notify.

DIAGRAM {BUS COUPLER AND BUZZER(ALARM/HOOTER) AT SEALDAH POWER HOUSE H.T.PANEL}::

ISOLATOR

In electrical engineering, an isolator switch is used to make sure that an electrical circuit can be completely de-energised for service or maintenance. Such switches are often found in electrical distribution and industrial applications where machinery must have its source of driving power removed for adjustment or repair. High voltage isolation switches are used in electrical substations to allow isolation of apparatus such as circuit breakers transformer and transmission lines for maintenance.

BUS COUPLER

Bus coupler provides electrical isolation bus by employing coupling transformers and fault isolation resistors. The Bus couplers contain two isolation resistors {one per wire} and an isolation transformer {with a ratio one to the square root of two}. The purpose of bus coupler is to prevent a short on a single stub from shorting the main data bus. The buses of two different voltage levels cannot be connected in series. So, bus coupler is used to join the buses of different voltage level.

PROTECTIVE RELAYS

A relay is fault sensing device. Many relay use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuit) or where several circuits must be controlled by one.

Signal. The first relays were used in long distance telegraph circuits, repeating the signal coming in form one circuit and re-transmitting it to another. Relays were extensively used in telephone exchanges and early computers to perform logical operations.

A type of relay that can handle the high power required to directly control an electric motor is called a conductor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called “protective relays”.

The Relays used in Sealdah Power House are of mainly two types:

OVER CURRENT RELAY EARTH FAULT RELAY

THE RELAY SPECIFICATION::{SPECIFICATION BASED ON ONE SAMPLE ON H.T. PANEL

OVER CURRENT RELAY EARTH FAULT RELAYModel No. CDG31EG001SBCH Model No. CDG31EG001SBCHSERIAL NO. 130954160621011 SERIAL NO. 130954160621011C.T. SEC: 5 AMPS;2.5-10 AMPS C.T. SEC: 5 AMPS;1-4 AMPSFREQUENCY:50HZ FREQUENCY:50HZ

OIL CIRCUIT BREAKER{O.C.B}:: The oil in OCB’s serves two purposes. It insulates between the phases and the

ground, and it provides the medium for the extinguishing of arc. When electric arc is drawn under oil, the arc vaporises the oil and creates a large bubble that surrounds the arc. The gas inside the bubble is around 80%hydrogen, which impairs ionisation. The decomposition of oil into gas requires energy that comes from the heat generated by the arc. The oil surrounding the bubble conducts the heat away from the arc and thus also contributes to deionisation of the arc.

Main disadvantage of the Oil Circuit Breaker is the flammability of the oil and the maintenance necessary to keep the oil in good condition.

THE OIL CIRCUIT BREAKER SPECIFICATION ::{BASED ON

ONE SAMPLE ON L.T.PANEL ON 1.NO PF SUB STATION }

SL.NO 2K2132 TYPE HN2T NORMAL CURRENT 400A SERVICE VOLTAGE 415V DESIGN FREQUENCY 50HZ BREAKING CAPACITY 25MVA TRIP COIL RATING 5A CALIBRATION 100/200% C.T. RATIO 800/5

Protection circuit breakers of electrical machines {generators, motors, transformers, capacitors}. They are used in all type of plants {civil, industrial, and in the service selector} as well as in the equipment on-board ships, in mines, in prefabricated substations, and for primary and secondary distribution in general.

THE AIR CIRCUIT BREAKER SPECIFICATION:: {SPECIFICATION BASED ON ONE SAMPLE ON L.T.PANEL}

MAKER PULSER FRAME LH800 DM 1T3P SL.NO. Y606183 IEC-947-2 IS:13947{PART-2} UTILIZATION CATEGORY 8

RATED CHARACTERISTICS

IN 400A

ITH@40 DEGREE C 800A ICS & ICU 50Ka ICW 50Ka,1sec POWER FACTOR 0.25 Ui=1000VUe=415V FREQUENCY: 50/60HZ U/V 40AC

DIAGRAM {AIR CIRCUIT BREAKERS}

o THE SCHEMATIC DIAGRAM OF AIR CIRCUIT BREAKER DISTRIBUTION SYSTEM

o A DISTRIBUTION SYSTEM FROM 11KV SUBSTATION

o SCHEMATIC DIAGRAM OF 6KV DISTRIBUTION ARRANGEMENT IN SEALDAH

o SF6 CIRCUIT BREAKER

3. THE RAJDHANI EXPRESS

TRAINING PERIOD: 01/07/2014 TO 04/07/2014

INTRODUCTION

Rajdhani Express is a passenger train service, offered by the Indian Railways, operating between New Delhi and other important destinations, especially state capitals.

Rajdhani Express was introduced in 1969, for providing fast connections (up to 140 km/h or 87 mph, speed variation depending upon the particular track section) from New Delh i to the capital cities of various states in India. The first Rajdhani Express left New Delhi station for Howrah station to cover a distance of 1,445 km in 17 hours 20 mins.

This superfast train service get highest priority on the Indian railway network. They are fully air-conditioned. Passengers are served complimentary meals during the journey. Depending on the duration and timings of the journey, these could include Morning Tea, breakfast, lunch, high tea, and dinner.

Presently the technology used in these trains has been obtained from Germany, with each individual coach built and exported by LINKE-HOFMAN & BUSCH(known as the LHB coaches).The newest coaches are said to be manufactured by a German company ALHSTORM.

This superfast train service runs on electric locomotives drawing power from overhead 25 kV lines with the help of Pantographs. However power required for lighting, heating, air conditioning purposes is generated using Diesel Generator sets(known as D.G sets), implementing EOG(End on Generation) with two power cars at the two ends of the train.

All Rajdhani Express trains offer three classes of accommodation: AC First Class with 2- or 4-berth lockable bedrooms, AC 2-tier with open berths (bays of 4 berths + 2 berths on the other side of the corridor) with curtains for privacy, and AC 3-tier (bays of 6 berths + 2 berths on the side) with curtains for privacy(according to recent directive the curtains in all 3 tier accommodations have been removed).

POWER SCHEME IN RAJDHANI EXPRESS

The components used in the power supply system consists of the following components :

Diesel Generator(DG ) set(2 in each power car ) comprising diesel generator and an alternator coupled together.

Reactor Inter Vehicular coupling(known as Z-S coupler) between

coaches.

Transformers Disconnecting and Earthing Device Battery Box Fuses Air conditioning system Water Heater Lights, fans, pantry,etc.

D.G SET :

Each Power car has two diesel engines coupled with alternators for power generation. Each alternator produce 750 V ac supply ,with a capacity to provide approx. 385 ampere current .Each coach requires about 40 ampere current .Generally the efficiency is around 80% so about 300 amperes can be used .

Diesel Engine : The Diesel engines are manufactured by Cotton-Greaves .The engine provides the mechanical energy required to rotate the alternator shaft for electrical power generation. Each engine produces 496 BHP of mechanical energy.

Alternator :The alternator is coupled with the diesel engine .Each power car has two alternators. The alternator specifications are as follows:-

Alternator Specifications:-

MAKER KIRLOSKER ELECTRIC CO. LTD

FRAME 4AB355/7 KVA 500 KVA EXTR. A.C R.P.M 1500

VOLTS 750V AMPS 385A EXTN. 280V EXTN. 1.5A FREQUENCY 50 Hz PHASE 3 P.F 0.8 CONNECTION Y COOLING TEMPERATURE 55 DEEGREE C

The voltage required for usage for the appliances in the coaches is 415 V. But the alternator generates more voltage because there are transmission losses from the power car to the coaches.

D.G SET INSIDE POWER CAR

INDUCTIVE REACTOR: The power generated in an ideal alternator is totally sinusoidal without any unwanted surges and other harmonics .Only the primary harmonics present in the signal. Among them the odd order harmonics specially the 3rd order harmonics can damage the electrical equipment severely .The reactor is used to remove these unwanted signals and provide pure sinusoidal signal.

REACTOR SPECIFICATION

MAKER KERALA ELECTRICAL AND ALLIED ENGG. CO. LTD.

VOLTS 125V

AMPS 50A FREQUENCY 150 Hz PHASE 1 INSULATION CLASS CLASS H INSULATION LEVEL AC3 TYPE OF COOLING AN MAX TEMP. RISE 115 DEEGREE C CORE AND WINDING 60KG TOTAL WEIGHT 110 KG

INTER-VEHICULAR COUPLING :

The power generated at the power car alternator is supplied to the coaches via inter – vehicular coupling or ZS coupling.

The fixed transmission lines are not used in the supply system. Because if any of the coaches is needed to be removed for maintenance or some other purpose then the transmission line is to be cut, which is not a good operation. At the time of coach removal, coupling is opened and the coach is disconnected from the supply. At the time of maintenance the coupling is connected to the dummy connector at the coaches.

I-V COUPLING

DISCONNECTING AND EARTHING DEVICE :

While maintenance all the live supplies are to be removed and switched off. While starting the maintenance the device disconnects all supplies and after the job completion the device connects the coach to the supply.

BATTERY BOX:

Under each coach there is a battery box. This is used for back up supply to the coaches. Each box supplies 110V DC. Each box contains 9 batteries and each battery supplies 12.2 V DC. The batteries are charged by regulated battery chargers (RBC) in side of each coach. If somehow this unit fails to charge the battery the Emergency Battery Charger (EBC) charges the battery.

Operation of RBC and EBC:

Regulated battery charger can sense the battery condition whether it is to be charged in the float mode (fully charged) or in boost mode (discharged below a certain level). Thereby it chooses the charging voltage. RBC consists of a rectifier and a step down chopper circuit. Rectifier unit converts 415V, 3 phase 50 Hz AC to 130V DC and step down chopper i.e. the DC to DC converter converts 110V to 24V.

In float mode the battery set of LHB EOG coach gets charged with a voltage of 121.5V i.e. 13.5V per mono block and in boost mode it gets charged with 128.5V – 129V.

When RBC fails to operate Emergency Battery Charger starts to operate giving a constant supply of 115V – 118V to the batteries.

When EBC also fails we can observe the backup time for other components from MVR (Minimum voltage relay) card.

When both the battery chargers fail to operate then the contact no. 8 gets opened instantly, resulting in turning off the PA system and the Music system.

After next 30 minutes of the failure the contact no. 9 gets opened resulting in turning off the water pump system.

After next 8 minutes of turning of the water pump system the contact no. 10 gets opened resulting turning off the lighting circuit.

Battery box under the coach

TRANSFORMER:

The power generated in the alternator is 750V. This is much higher than the required value. The Transformers are used to step down the voltage level to 415V AC. The transformers are located under the coaches.

Under each coach there is one transformer to supply power (excluding pantry cars which have two transformers for each coach).

Transmormer Specifications:

MAKER Vimal Transformer Corporation INPUT 750V AC OUTPUT 415 V AC CAPACITY 60 KVA FREQUENCY 50Hz IMPEDANCE <4% LINE AMP. 46.2A OUTPUT 83.2A WEIGHT <440KG VECTOR CONNECTION Y.Y.O VECTOR TYPE Primary :Star Secondary :Delta

WATER PUMPS:

The 750V AC coming from the alternators is stepped down to 3 phase 415V AC by the 60 KVA transformer. This 415V AC drives two centrifugal pumps located in a stainless steel casing at the under frame supply the water to the tanks. One of the 415 V pumps is always kept running, while

the other is kept on standby for 4 hours maximum. After 4 hours a microcontroller switches the operation to the other pump. These supply water in the coaches.

THE COACH CONFIGURATION OF SEALDAH–NEW-DELHI

RAJDHANI EXPRESS

Almost every Rajdhani Express offers three classes of accommodation:

First class AC with 2 or 4 berth lockable bedrooms AC 2 tier with open berth with curtains for privacy AC 3 tier with curtains for privacy

The Rajdhani Express contains 20 coaches in total. The coaches are as below::

First class AC: 1 coach :H1 AC 2 tier: 3 coaches : A1-A3 AC 3 tier: 10 coaches :B1-B12 Pantry car: 2 coaches :PC Power car: 2 coaches :EOG

The coach configuration is as follows:

Rake/Coach Composition

LOCO-EOG-H1-PC-A3-A2-A1-B12-B11-B10-B9-B8-B7-B6-B5-B4-B3-B2-B1-PC-EOG

LINKE-HOFMANN-BUSCH COACHES

Linke Hofmann Busch (LHB) coaches are the passenger compartments of Indian Railways that have been developed by Linke-Hofmann-Busch of Germany (renamed Alstom LHB GmbH in 1998 after the takeover by Alstom) and produced by Rail Coach Factory in Kapurthala, India. The coaches are designed for an operating speed up to 160 km/h and could go up to 200 km/h. However, they have been tested up to 180 km/h. Their length of 23.54m and a width of 3.24m means a higher passenger capacity, compared to conventional rakes. The tare weight of the AC chair car was weighed as 39.5 Tons.

They are considered to be "anti-telescopic", which means they do not get turned over or flip in case of a collision (chiefly head-on). These coaches are made of stainless steel and the interiors are made of aluminium which make them lighter as compared to conventional rakes. Each coach also has an "advanced pneumatic disc brake system" for efficient braking at higher speeds, "modular interiors" that integrate lighting into ceiling and luggage racks with wider windows. The improved suspension system of LHB coaches ensures more riding comfort for the passengers compared to conventional rakes. The air conditioning system of the LHB coaches is of higher capacity compared to the older rakes and is controlled by a microprocessor which is said to give passengers better comfort than the older coaches during summer and winter seasons. They are relatively quieter as each coach can produce a maximum noise level of 60 decibels while conventional coaches can produce 100 decibels. Each LHB coach costs between Rs 15 million to 20 million, whereas the power car which houses a generator costs about 30 million.

LHB coaches of the Rajdhani Express

Here’s a list of the Circuit diagrams to be included in these pages that were xeroxed by us:-

1.layout inside and underframe

2.layout roof

3.inside viw of lhb coach panel s-1

4.single line diagram of power circuit of lhb coaches

5.wiring diagram of microproccesor wiring diagram of ebc and rbc

6. wiring diagram of lighting circuit power and control

AC 2 TIER & AC 3 TIER COACHES:

The train has 3 AC 2 tier and 10 AC 3 tier coaches. Each coach gets its own power supply from the transformer below

them. The 3 tier (6+2 berth) and the 2 tier (4+2 berth) coaches have their own

controlling and safety units at the ends of the coaches. Each coach is provided with music system and announcement system

which is controlled from the panels at the end. Each coach has its own storage selection for food and water. For this

purpose 2 deep freezers, 2 bottle coolers and 2 hot cases are provided. This unit is operated by the compressors and the blower motors of its own mounted below this unit.

FIRST CLASS AC COACH:

The train has only one first class AC coach.

This may contain 2 berths or 3 berths system. The coach has controllable music system. The announcement and the

music volume can be regulated in the first class compartment. The first class coach does not have any bottle cooler or freezer.

THE PANTRY CAR:

The pantry car is the coach to supply food to the passengers and the staff members.There are two pantry cars at the two ends of the train after the power cars.

The different components of the pantry car are as follows:

EQUIPMENT DESCRIPTION

LOAD (WATT)

QUANTITY TOTAL LOAD(WATT)

Deep Freezer, 230ltr

400 1 400

Bottle cooler 90ltr 200 1 200Hot case 140 meals

1600 1 1600

Insect killers 20 2 40Oven toaster Grill 1200 1 1200Water boiler1 2000/3000 1 2000/3000Water boiler2 2000/3000 1 2000/3000Water boiler1 2000/3000 1 2000/3000Electric burner 1 2000 2 4000Electric burner 2 2000 1 2000Electric burner 3 2000 1 2000Electric burner 4 2000 1 2000Refrigerator, 310 ltr

300 1 300

Electric chimney 1 300 1 300Electric chimney 2 300 1 300Electric chimney 3 300 1 300Total load (watt) with 2000 Watt water boiler 28540Total load (watt) with 3000 Watt water 31540

boiler

Due to all these high rating equipments are housed in the pantry car, it requires more electric supply than other coaches.

Due to the operation of the heater, water boiler and other high loading elements there are much more risk for fire hazards. To deal with this problem the Smoke Detector is kept mounted in the ceiling of the car connected with alarm system. The smoke detector has a simple thermostat switch that automatically switches on the alarm under critical conditions.

An inside view of the pantry car

AIR CONDITIONING SYSTEM

Principle of Operation of the AC System

The air-conditioning process maintains a constant climatic condition by controlling temperature, humidity, cleanliness, noise and air motion. The air-conditioning system includes both refrigeration and heating.

The refrigerating system depends for its action of the following principles.

(i) Latent principle Any substance in passing from the liquid to gaseous state absorbs at constant temperature s specific quantum of heat known as the latent heat of evaporation and gives up latent heat on passing from gaseous to liquid state.Application: Evaporator and Condenser

(ii) Expansion principle When a gas expands without external heat exchange it temperature falls and when it is compressed without external heat exchange its temperature decreases.The air-conditioning system adopted in air-conditioned coaches work on mechanical compression system and consists of the following:

Evaporator unit consisting of cooling coil(heat exchanger), heater and motor-driven blower unit.

Thermostatic expansion valve. Motor-driven compressor. Air cooled condenser (with cooling fan driven by motor) Liquid receiver and dehydrator. Refrigerant piping for conveying the refrigerant(R-134A).

The Refrigeration Cycle

A typical refrigeration cycle in an air-conditioned coach can be represented also in a pressure enthalpy diagram as in figure. The refrigerant gas at low pressure (represented by point C) is compressed to point D. The compression process elevates the pressure from 37 psi(maximum 46 psi) to 150 psi(maximum 180 psi). The compression of the gas also heats up the gas to a superheat condition. The gas at the compressor outlet is superheat and latent heat are removed at constant pressure , the refrigerant reaching the point A at the end of this part of the cycle. The line A-B represents the expansion that takes place in the expansion valve while the line B-C represents the refrigeration effect that is obtained in evaporator.Apart from cooling, the air conditioning equipment is also required to provide heating when the outside temperature varies from 400 C to 200

C .The cooling and heating will nave be necessarily automatic by means of thermostatic controls incorporated in the unit. RDSO specification also lays down that the equipment shall admit fresh air at the rate of 0.35 metro

cube per minute per passenger in the non-smoking area and 0.7 meter cube per minute per passenger in the case of compartments where smoking is permitted.

Description of various components of Air-conditioning System.

Evaporator unit

The evaporator unit consists of a thermostatic expansion valve, a heat exchanger, a resistance- heating unit and a centrifugal blower driven by a motor. The function of the thermostatic expansion valve is to allow the compressed refrigerant liquid to expand to a lower pressure corresponding to the load demand. The expanded refrigerant passes through a heat exchanger; the heat in the air is transferred to the refrigerant causing the cooling of the air and the evaporation of the refrigerant inside the tubes. The cooled air is led through the ducting to the various compartments and diffused by means of air diffusers. Fresh air is drawn through filters to eliminate dust and is mixed with the return air in the plenum on the inlet side of the evaporator. Similarly, the return air filters so that the dust contained air in the return air is extracted. When the outside ambient is very low and when the refrigeration is not required, the heater is switched on according to the setting of thermostat.

Expansion valve

The primary function of the expansion value is to control the quantity of liquid refrigerant admitted into the cooling coils of the evaporator.. The expansion valve admits more refrigerant when the air conditioning load is high, and reduces it to the minimum when the load is low.If the airconditioning load varies greatly the superheat may be set between 101 O F to 150O F.

Compressor

The refrigerants vapour drawn from the evaporator is compressed by means of a multi cylinder reciprocating compressor. The work done due to compression raises the temperature of the refrigerant vapour.

Condenser

The condenser serves the function of extracting the heat absorbed by the refrigerant vapour in the evaporator and the heat absorbed during the compression process. The condenser consists of a heat exchanger, which is force-cooled by means of two or three axial flow blower fans. The refrigerant vapour is cooled at constant pressure by means of the air blown over the finned tubes and liquefied. The refrigerant liquid leaving the condenser is led into the liquid receiver from where it proceeds to the expansion valve on the evaporator. The liquid receiver is a cylindrical container which contains a reserve of the refrigerant liquid. A dehydrator and filter are also provided to ensure that the refrigerant is free from moisture and dust particles.

High Pressure Cot-out

The high pressure cut-out is essentially a safety device against build up of excessive delivery pressure and protects the compressor and piping system from damage. I t is a pressure operative switch which switches off the compressor drive motor when the pressure exceeds a preset valve.

Low Pressure cut-out

This is also a pressure operated switch similar to the high pressure cut-out switch, but is shuts down the compressor if the suction pressure drops down below 10 psi gauge. It protects the system against unduly low evaporator temperatures and formation of frost on the evaporator.

Dehydrator and Filter

Water vapor or moisture will cause trouble in any refrigeration system. The moisture may freeze and block the expansion valve orifice, and. also cause

corrosion in working parts. This is best achieved by subjecting the system of vacuum for 2 or 3 days. The dehydrator is another drying device containingsilicalgel or other similar drying agent inserted in the refrigerant load for removing moisture from the refrigerant while in operation. It should be provided atleast temperature when the installation is brought into operation to remove any moisture in the piping system.

Refrigeration piping

The refrigerant piping consist of the suction line(from the evaporator outlet to the compressor inlet) and the discharge line(from the compressor outlet to the condenser inlet), and liquid line(from the liquid receiver to the inlet side of the expansion valve). Connections to the gauge panel from the compressor delivery side(high pressure side), low pressure side and from the compressor crankcase, the lubricating oil connections, are also part of the piping system, only copper pipes are used for refrigerant piping.

AC Control Panel:-

The control of the airconditiong system is achieved by means of Airconditioning Control Panel.

A.C. Control Panel Components and their functions

Evaporator Fan Motor Contactor- Controls the supply of the evaporator motor.

Evaporator Fan Motor Proving Relay- The prevents energisation of the compressor motor and condenser motor or Heater till trio evaporator motor (16) comes ’ON’ and blows air into the duct through the evaporator coil. This relay works in conjunction with a “Vone Switch” provided in trio air circuit. If the evaporator blower motor supply fails or the motor does not run, the compressor motor and the condenser motors/Heater will get switched ‘OFF’ by this relay.

Low Voltage Relay- This will trip to stop the compressor motor and condenser motors/heater, and prevent them from starting by cutting off the supply to their control circuit if the voltage of the battery is below 100 and reset when battery voltage rises to 102 V. The relay is provides with a build-in time delay f 5 seconds, to avoid nuisance – tripping.

Cooling Pilot Relay – Acts as an electrical link between the cooling thermostats and the control circuit of the compressor and condenser. This is energized by electronic triggering set off by heat thermostat.

Heating Pilot Relay- Acts as an electrical link between the heating thermostats and the control circuit of heater. This is energized by electronic triggering set off by thermostats.

Main Control Switch- This is the control switch for starting or shutting down the plant. This has got provision to select blower only, LOW,MEDIUM and HIGH temperature setting.

Single thermostat ,i.e Electronic thermostat is used for heating & cooling purpose.

Oil pressure Cut-out Switch- This protect the compressor against lubrication failure either due to lesser oil oil pump failure or blocking of oil piping, and acts in conjuction with thermal cut-out to shut down the compressor only if the low oil pressure persists.

Low pressure cut out- A pressure switch to protect against working of compressor with low suction pressure due to loss of Freon gas or other reasons. This switch has been connected by means of copper piping to the suction header of the compressor.

High pressure cut-out- A pressure switch to shut down the compressor when compressor discharge pressure is too high. The switch has been connected to the compressor discharge header by means of copper piping.

Pilot lights- These lights indicate respectively normalcy oh the mains , blower fan motor, compressor motor, heater and normal voltage. Indications are now by LEDs.

Desirable properties of the refrigerant:-

It should be non-irritating, non-poisonous, non-inflammable and have no faning effect on food stuffs if it escapes.

It should not have any corrosive action on any working part of the compressor , condenser and evaporator.

It should not have any disagreeable order. Leak detection should be easy and simple. Latent heat of vaporization should be large to minimize the

quantity of refrigerant used. The volume of vapor for given weight should be low to reduce the

size of the compressor. R-134a(Tetra fluro ethane) is used as refrigerant as it is

environment friendly replacing R-134a . It has excellent refrigerating properties and is the first choice for most air conditioning plant. It is safe, non-toxic, non-inflammable.

Comparison of roof mounted A.C system with conventional under frame Hung

1.Weight 900 Kg 2700Kg2.Installation Time 4 Hrs 4 days3. Refrigerant R-22 Monochlorodia

fluoro methaneR-134a Tetra flouro ethane

4. charge Less than 3.0 kg 15-20 kg5. system design Hermetically sealed Open6.Roof leak potential Nil Enormous7. Power Supply A.C Nil8.Damage due to Cattle run

Nil Heavy

9. Damage due to flash floods

Nil Heavy

10. Performance Excellent Deteriorates quickly due to dust collection

under coach11.Technology Latest Old and obsolete12.Water drop on Nil Passengers at end13.Fresh air From roof Takes from toilet14.Cpacity control 25%-100% 50-100%15.Down time for repairs

4 hrs Very long repair require