electric traction system and motors used in Electric traction system

2. ELECTRIC TRACTION SYSTEM
Presented by:
M.ibrar younas

3. Contents
 Electric traction.
 History of electric traction.
 Advantages and Disadvantages
 Motors used in electric traction.
 Advantages of AC system over DC

4. HISTORY OF ELECTRIC TRACTION
 The years 1881 saw the birth of the first electric railway
run by German Engineer Werner Van Siemens.
 Electric traction was introduced on indian railways in
years 1925 on 1.5 KV DC
 In the years of 1957,indian railway decide to adopt
25KV,50HZ AC traction based on French(SNCF)
technology.

5. WHAT IS ELECTRIC TRACTION
 Electric traction is meant for locomotion in which the
driving force is obtained from electric motors.
 It involves to utilization of electric power for traction
system.

6. ADVANTAGES
o High starting torque
o Lower running cost of locomotive & multiple units
o Less noise pollution
o Breaking system is very efficient & simple

7. DISADVANTAGES.
 Problem of supply failure
 High capital cost
 Electrically operated vehicles have to move on guided
track only

8. Motors Used In Electric Traction
Three motors used in electric traction.
D.C series motors.
Single phase A.C series motors.
Three phase induction motors.

9. D.C SERIES MOTOR.
 D.C series motor develops high torque at low speed
and low torque at high speed , exact requirement of
the traction units.
 D.C series motor torque is independent of the line
voltages.
 D.C series motor unaffected by the variations in the
line voltages/

10. CIRCUIT DIAGRAM &
CHARACTIRISTIC CURVE

11. SINGLE PHASE A.C SERIES MOTOR

12. CIRCUIT DIAGRAM

13. CHARACTERISTIC CURVE

14. 3-PHASE INDUCTION MOTOR
 Having constant speed
 Constant torque speed characteristics
 Low maintenance cost
 High efficiency

15. Circuit Diagram

16. Characteristic curve

17. Advantage of AC motor over DC
 Dc motor use commotators which are prone to failure
because of vibration and shock
 It is hard to use dc motor for regenerative breaking
 It use extra switch gear therefore system is bulkier
 Ac motor have simple construction