05-04-2012, 12:57 PM
diesel locomotive works Varanasi
45187594-Summer-Training-Diesel-Locomotive-Works-Ppt.ppt (Size: 1.87 MB / Downloads: 1,615)
Introduction
It is a production unit owned by Indian railways , for which it manufactures diesel–electric locomotive and its spares parts.
To meet the increased transportation needs of the Indian railways it was established in collaboration with M\s ALCO( American Locomotive Company), USA.
Founded in 1961, the D.L.W. rolled out its first locomotive three year later, on January 3, 1964. It manufactures locomotives which are variants based on the original ALCO design dating to 1960s and the GM EMD design of the 1990s.
It has evolved into an integrated diesel–electric locomotive manufacturing plant, capable of building all components of the locomotive in-house, including the engines, super structures, and fabricated bogies and under frames.
Diesel’s advantages over steam
They can safely be operated by one person, making them ideal for switching/shunting duties in yards.
The operating environment is much more attractive, being much quieter, fully weatherproof and without the dirt and heat that is an inevitable part of operating a steam locomotive.
Steam locomotives require intensive maintenance, lubrication and cleaning before, during and after use.
The thermal efficiency of steam was considerably less than that of Diesel engines.
PRINCIPLE OF DIESEL ENGINE
When the piston is at the top of its travel, the cylinder contains a charge of highly compressed air.
Diesel fuel is sprayed into the cylinder by the injector and immediately ignites because of the heat and pressure inside the cylinder.
The air in the cylinder is raised to about 500-600 psi which raises the temperature inside to about 1000 0 F.
The pressure created by the combustion of the fuel drives the piston downward. This is the “power stroke”.
. Crank shaft:
Most reciprocating internal combustion engines end up turning a shaft. This means that the linear motion of a piston must be converted into rotation. This is typically achieved by a crankshaft.
. Starter systems :
All internal combustion engines require some form of system to get them into operation. Most piston engines use a starter motor powered by the same battery as runs the rest of the electric systems.
Lubrication Systems:
Internal combustions engines require lubrication in operation that moving parts slide smoothly over each other. Insufficient lubrication subjects the parts of the engine to metal-to-metal contact, friction, heat build-up etc.
factors affecting tractive coefficient
Traction between two surfaces depends on several factors including:
1. Material composition of each surface.
2. Macroscopic and microscopic shape .
3. Normal force pressing contact surfaces together.
4. Contaminants at the material boundary including lubricants and adhesives.
5. Relative motion of tractive surfaces
In the design of wheeled or tracked vehicles, high traction between wheel and ground is more desirable than low traction, as it allows for more energetic acceleration (including cornering and braking) without wheel slippage.
Full-wave rectification
A full-wave rectifier converts the whole of the input waveform to one of constant polarity (positive or negative) at its output. Full-wave rectification converts both polarities of the input waveform to DC (direct current), and is more efficient. However, in a circuit with a non- centre tapped transformer, four diodes are required instead of the one needed for half-wave rectification. Four rectifiers arranged this way are called a diode