DEPARTMENT OF MECHANICAL ENGINEERING KRISHNA ENGINEERING COLLEGE, GHAZIABAD

A Seminar Report On “Engine Control” Submitted in Partial fulfilment of award of Bachelor of Technology   by   Pranchal Srivastava:- 1216140065

CONTENTS1. About Organisation2. Motive power directorate3. Alambagh loco shed4. Traction system5. Locomotive Basics 6. Traction Motor7. Basic Components8. Transiton system9. Excitation system10. REMLOT11. Summary

About Organisation• Railways were introduced in India in 1853

• Enforce standardization and co-ordination amongst various railway systems

• the Indian Railway Conference Association(IRCA) was set up in 1903• the Central Standards Office (CSO) in 1930

• Railway Testing And RESEARCH Centre was setup in 1952

MOTIVE POWER DIRECTORATE

Motive Power directorate has been engaged in designs and standards works related with diesel-electric, diesel-hydraulic and electric locomotives since 1960s.

Complete Design Development of Diesel-electric and diesel hydraulic locomotives

Technical investigations into operational and maintanence problems Indigenization of locomotive equipment Nodal directorate for IRS/BIS specifications

About Alambagh Locomotive shed

Alambagh diesel locoshed is located in Alambagh at Lucknow in UttarPradesh, Nearly 2 km from Charbagh Railway Station. It has around 150 diesel engines under its charge. It looks after maintenance of 150 diesel engines and also repairs engine if it breakdowns or fault occurs in its regionn. Alambagh diesel locoshed comes under north-eastern zone. It has various sections and schedules for maintenance of diesel engine as mentioned below. Under maintenance sections the fault is diagnosed, removed, altered, various parts of engine are unmounted , cleaned ,overhauled, tested and changed if it malfunctions.

Traction System

There Are AC-DC and AC-AC traction System used in Indian Railways ALCO loco has ac-dc traction system EMD (GM) loco has ac-ac traction system

Locomotive Electrics- Basic AC-AC System The system basically uses diesel engine, alternator, rectifier, d.c. link,

invertor(s) and asynchronous motors. The alternator is directly coupled to the diesel engine. The frequency of the alternator output varies with the speed of

diesel engine. The voltage is rectified and the power is fed through a d.c. link to the

inverter of the tractive system. Drive system uses asynchronous motors ENGINE -- ALTERNATOR -----INVERTER ----TRACTION MOTOR

Main Generator

A Diesel- Electric Locomotive uses A Main Generator to Control the Mechanical Power developed by diesel Engine into Electrical Power

It is basically two generators in one - two sets of stator windings, permanently connected in series, work with a rotating field common to both the windings in order to provide a higher generator output voltage

COMPANION ALTERNATOR

The main alternator has a companion auxiliary generator CA 6 for power supply to large auxiliaries. It is also the main excitation source for the main alternator. The companion alternator is an electrically independent machine and is mechanically coupled on the main shaft of the traction alternator. The companion alternator rotor field is excited directly by auxiliary supply of the locomotive (72+2 VDC)

AUXILLARY GENERATOR Auxiliary generator consists of a 3 phase pilot exciter assembly and a 3

phase AC auxiliary generator field and armature assembly The nominal output rating of AC auxiliary generator is 18 KW at 55 VAC

TRACTION MOTOR

An electric motor converts electrical energy into mechanical energy. Electrical power from inverters is distributed to traction motor mounted in trucks. Each motor is geared to a pair of wheels with a gear ratio (77:17) selected for intended service.

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

Traditionally, these were series-wound brushed DC motors, usually running on approximately 600 volts. The availability of high-powered semiconductors (such as thyristors and the IGBT) has now made practical the use of much simpler, higher-reliability AC induction motors known as asynchronous traction motors. Synchronous AC motors are also occasionally used, as in the French TGV.

Usually, the traction motor is three-point suspended between the bogie frame and the driven axle; this is referred to as a "nose-suspended traction motor".

The "Bi-Polar" electric locomotives built by General Electric for the Milwaukee Road had direct drive motors

The DC motor was the mainstay of electric traction drives on both electric and diesel-electric locomotives, street-cars/trams and diesel electric drilling rigs for many years. It consists of two parts, a rotating armature and fixed field windings surrounding the rotating armature mounted around a shaft.

The asynchronous motor with a squirrel cage rotor is the simplest of all electrical machines. When fed by a 3- phase alternating voltage, a magnetic field rotates in the stator. The speed of rotation of this field is directly proportional to the frequency of the A.C. voltage.

MAIN CIRCUITS COMPONENTS

a. Contactors are switches used for opening and closing circuits.they are also known as power switches.

In circuits where the current is low, the contactors are magnetically operated and are energized by current from the battery

b. Interlocks are auxiliary switches designed to control the connecting or breaking of circuits

c. A magnet valve consists of a magnet coil and a core acting upon an air valve. The coil is in the low-voltage control circuit and connected through interlocks, automatic controls, or manual controls in the same manner as the coil on a contactor

d. A relay, a small magnetic electric switch consisting of a coil and several small contacts, changes connections in one part of a circuit in response to changes taking place elsewhere in the circuit.

TRANSITION SYSTEM

PURPOSE  To obtain higher speed of the locomotive and still utilize the constant

horsepower of the engine at a speed setting of the engine

WHAT IS THE PROBLEM

  At starting, and at low locomotive speeds, the main generator supplies a high current to the traction motors

As the traction motor armatures begin turning, they generate a voltage commonly called back EMF, which as if increases the effective resistance to the current flow

If the back EMF reaches the voltage limit of generator, the generator current starts falling and the horsepower reduces

The motor current will have dropped so much that continued acceleration would not be possible at reduced horsepower along the field limit line

HOW TO AVOID

 By changing the generator motor connections, the back voltage is reduced and the generator can force more current to the motors to enable acceleration

To achieve higher starting torque, sometimes, two traction motors are connected in series during starting of the locomotive

In these locomotives, changing their connections from series to parallel can reduce the back EMF.

Weakening the motor fields can also reduce back EMF.

EXCITATION SYSTEM

WHAT IS EXCITED AND WHY The voltage output of a generator depends on the speed of the

armature and the amount of field excitation. The current, on the other hand, depends on the circuit connected to the generator (usually called "load"). In a diesel electric locomotive, the load is the combination of traction motors connected with their cables and switches. These motors should have the right voltage at all the times to ensure proper generator output. To get the right voltage, the current in the generator field must be varied to suit the locomotive operating conditions. This is known as excitation control

JOB OF A LOCOMOTIVE

A diesel electric locomotive must be able to start a heavy train, bring it up to running speed, slow it down and stop it.

Starting and gaining speed require a large amount of torque on the wheels.

As the traction motors drive the wheels, they must develop a large amount of torque to start a train.

Then as it speeds up, less and less torque is required.

JOB OF EXCITATION SYSTEM

A diesel engine gives maximum fuel efficiency if it is loaded in such a way so that it develops constant HP with each throttle setting. In a diesel electric locomotive, load is the combination of traction motors, and the current through them varies with their change in speed. So to keep main generator output power constant, the output voltage must be varied accordingly.

Excitation system panel with cards

REMLOT

REMMLOT Enables remote monitoring of Diesel Locomotives. It creates a complete ITenabled ecosystem which provides a platform for remotely monitoring health andoperational characteristics of diesel electric locomotives.

It also enables monitoring of performance of crew and helps in identifying lapses, e.g.when he passes a signal at danger. This will enable focused counselling and training ofsuch crew, who are prone to unsafe working.

REMMLOT also monitors condition of locomotive and makes preventive maintenance oflocomotives more effective. REMMLOT monitors shutting down of locomotives when idlefor a long time and generates management information to ensure this.

Summary The Diesel Electric Locomotives of Indian Railways, driven by DC traction motors,employ AC/DC Power Transmission System. Traction Alternator is directly coupled with Diesel Engine. The three-phase output of the

Alternator with variable frequency and voltage, depending on RPM of Diesel Engine and Excitation level of the Alternator, is fed to a Rectifier Panel.

At starting the motors are connected in series-parallel (e.g. in WDG series locomotive with 6 motors locomotive starts in 2 series-3 parallel mode). When a specified Locomotive speed is achieved, Motor Transition takes place by changing the connection configuration of Traction Motors to series to series weak field or series weak field to parallel (6P) and vice versa when the speed is reduced as per setting done in the configuration parameters