15-06-2012, 01:29 PM
ELECTRIC TRACTION
ELECTRIC TRACTION.pptx (Size: 1.5 MB / Downloads: 322)
What is a traction?
The act of drawing or pulling.
When the above act is done by electricity, then it is nothing but electric traction.
Electric traction also means a locomotive in which the propulsion (tractive or driving) is obtained by the use of electricity.
Electrification System:
Electrification systems are classified by three main parameters:
Voltage
Current
Contact system
Current
a)Direct current: The DC system is quite simple but it requires thick cables and short distances between feeder stations because high currents are required.
b)Alternating current: These are overhead electrification systems. Alternating current can be transformed to lower voltages inside the locomotive.
Contact System
a)Over head system: The supply of electricity is through an overhead system of suspended cables known as the catenaries.
b)Third rail system: A third rail is a method of providing electricity to power a railway through a continuous rigid conductor alongside the railway track or between the rails.