Introduction, Merits, Demerits, Ideal System, Power Supply for Electric Traction System

1. ELECTRIC TRACTION
-Mr. V. S. Wadkar

2. CONTENTS
• Introduction
• Requirements of Ideal Traction System
• Merits of Electric Traction System
• Demerits of Electric Traction System
• Supply Systems for Electric Traction

3. INTRODUCTION
• Traction is the action of drawing or pulling
something over a surface, especially a road
or track.
• Classification of Traction Systems:
> Non-Electric
> Electric

4. 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,
diesel-electric vehicles and gas turbine electric
vehicles

5. EXAMPLES OF TRACTION
SYSTEM
• Non-electric traction systems:
-Steam engine drive
-IC engine drive
• Electric traction systems :
-Electric drive
-Diesel electric drive
-Gas turbine electric drive

6. IDEAL TRACTION SYSTEM
-REQUIREMENTS
• The starting tractive effort should be high
• 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

7. ELECTRIC TRACTION - MERITS
• Cleanliness, Less maintenance
• Starting Time
• High efficiency
• High starting torque
• Less running cost
• Duty cycle is more
• More Flexibility
• Electrical braking
• High speeds

8. ELECTRIC TRACTION - DEMERITS
• High capital cost
• Supply failure
• Disturbance with communication lines
• Additional equipment is required for achieving
electric braking and control

9. 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 (Kando System)

10. SUPPLY SYSTEMS FOR
ELECTRIC TRACTION
• D.C system
- Use of DC series motor
- High Starting Torque
- Easy Speed Control
- Low Maintenance Cost
- 600V to 3000V

11. SUPPLY SYSTEMS FOR
ELECTRIC TRACTION
• Composite system
– Single phase AC to DC
- Transformer and rectifier for
conversion
- Use of DC Series motor
• Composite system
– Single phase to three phase (Kando System)
- Phase converter equipment is required
- Use of Three phase induction motor

12. Comparison between AC and DC System
DC System AC System
DC Series motor - High starting and
running torque
AC Series motor - Low starting and
running torque
DC Series motor - Less costly, Light in
weight, Less maintenance, More
efficiency
AC Series motor - More costly, More
maintenance, Less efficiency
Regenerative braking is more efficient Regenerative braking is less efficient
No interference with communication lines Interference with communication lines
Speed control is difficult Speed control is easy
More substations are required Less substations are required
Overhead system is more costly Overhead system is lighter and less costly