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Eletric Traction

This document discusses electric traction systems for transportation. It describes how electric traction works by using electric motors as the driving force rather than steam or internal combustion engines. There are various types of electric traction including electric trains, trolley buses, and diesel-electric or gas turbine electric vehicles. The document outlines the different systems of traction that exist, components involved like traction motors, and methods of controlling and braking electric traction.

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Gowri Sri Gowri
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5K views21 pages

Eletric Traction

This document discusses electric traction systems for transportation. It describes how electric traction works by using electric motors as the driving force rather than steam or internal combustion engines. There are various types of electric traction including electric trains, trolley buses, and diesel-electric or gas turbine electric vehicles. The document outlines the different systems of traction that exist, components involved like traction motors, and methods of controlling and braking electric traction.

Uploaded by

Gowri Sri Gowri
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPT, PDF, TXT or read online on Scribd
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ELECTRIC TRACTION

INTRODUCTION:
The locomotion in which the driving force is obtained from electric motor is called the electric traction system. There are various system of electric traction existing such as electric train, trolley buses, dieselelectric vehicles and gas turbine electric vehicles

ELECTRIC TRACTION SYSTEM

MAJOR CLASSIFICATIONS OF
TRACTION
Non-electric traction: examples steam engine drive ic engine drive Electric traction: examples diesel electric drive gas turbine electric drive

REQUIREMENTS OF AN IDEAL TRACTION


SYSTEM The starting tractive effort should be high so as to have rapid acceleration. The wear on the track should be minimum. The equipments should be capable of withstanding large temporary loads. Speed control should be easy. Pollution free. Low initial and maintenance cost. The locomotive should be self contain and able to run on any route.

MERITS OF ELECTRIC TRACTION


High starting torque. Less maintenance cost Cheapest method of traction Rapid acceleration and braking Less vibration Free from smoke and flue gases hence used for underground and tubular railway.

DEMERITS OF ELECTRIC TRACTION


High capital cost. Problem of supply failure. The electrically operated vehicles have to move on guided track only. Additional equipment is required for achieving electric braking and control.

DIFFERENT SYSTEMS OF TRACTION:


Direct steam engine drive Direct IC engine drive Steam electric drive IC engine electric drive Petrol electric traction Battery electric drive Electric drive

IC ENGINE ELECTRIC DRIVES

SUPPLY SYSTEMS FOR ELECTRIC TRACTION:


D.C system A.C system

Single phase Three phase


Composite system
Single phase AC to DC Single phase to three phase

SPEED TIME CURVE FOR TRAIN MOVEMENT

Acceleration

Constant acceleration Speed curve running

Free run or constant speed period Coasting period Retardation or braking period

TYPICAL SPEED TIME CURVES FOR DIFFERENT


SERVICES Urban or city services Sub urban services Main line services

TYPES OF SPEED IN TRACTION crest speed Average speed Schedule speed

FACTORS AFFECTING ENERGY CONSUMPTION


Distance between the stops. Train resistance Acceleration and retardation. Gradient train equipment.

TRACTION MOTORS
DC series motor Ac series motor Three phase induction motor

TRACTION MOTOR ELECTRICAL FEATURES


High starting torque Simple speed control Regenerative braking Better commutation Capability of withstanding voltage fluctuations. MECHANICAL FEATURES Light in weight. Small space requirement. Robust and should be able to withstand vibration.

TRACTION MOTOR CONTROL


Rheostat control Series parallel control Field control Buck and boost method Metadyne control Thyristor control

Phase control Chopper control

BRAKING
ELECTRIC BRAKING Plugging or reverse current braking Rheostatic braking Regenerative braking
DC shunt motor DC series motor Induction motor

MECHANICAL BRAKING Compressed air brakes Vacuum brakes MAGNETIC TRACK BRAKES

RECENT TRENDS IN ELECTRIC TRACTION


Tap changer control Thyristor control Chopper control Micro processor control

MICRO PROCESSOR CONTROL

QUESTIONS ?

If fail to Plan, you plan to fail

THANK
YOU

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