22-11-2012, 02:22 PM
DIESEL-ELECTRIC LOCOMOTIVES: TRACTION ASSEMBLY AND LOCOMOTIVE TESTING
DIESEL-ELECTRIC LOCOMOTIVES.pdf (Size: 462.31 KB / Downloads: 95)
4000 HP GOODS LOCOMOTIVE Broad Gauge freight traffic Co-Co diesel electric locomotive with 16 Cylinder 4000 HP engine, AC-AC transmission, microprocessor controlled propulsion and braking with high traction high speed cast steel trucks.
Diesel Engine 16 Cylinder 710 G3B, 2 stroke, turbocharged – after cooled Fuel Efficient Engine
7
Injection System – Direct Unit Injector Governor – Woodward Compression Ratio- 16:1 Lube Oil Sump Capacity – 950 Lts
Transmission Electrical AC-AC 6 Traction motor ( 3 in parallel per bogie) Suspension – Axle hung / taper roller bearing Gear Ratio – 90:17
WDP4 – 4000 HP PASSENGER LOCOMOTIVE State-of-Art, Microprocessor controlled AC-AC, Passenger Locomotive Powered with 16-710G3B 4000HP Turbo charged Two stroke Engine. Fabricated rigid design Under frame, two stage suspension, High Traction High Speed 3 axle (HTSC) light weight cast truck frame attribute to high adhesion performance.
Diesel Engine 16 Cylinder 710 G3B, 2 stroke, turbocharged – after cooled Fuel Efficient Engine Injection System – Direct Unit Injector Governor – Woodward Compression Ratio- 16:1 Lube Oil Sump Capacity – 1073 Lts
Transmission Electrical AC-AC 4 Traction motor ( 3 in parallel per bogie) Suspension – Axle hung / taper roller bearing
TAS: TRACTION ASSEMBLY SHOP TAS is the unit in which all the locomotive parts are assembled, that include:
1. CP (Control Panel)
2. Alternator
3. Traction Motors
4. 16 cylinder Diesel Engine
5. Master Control
6. Cab
7. Auxiliary Generator & Exciter
8. Governor
9. Crank Case Exhauster
10. Mechanical Assembly
1. Control Panel The CP or the Control Panel (wrt WG3A loco) consists of: Control Switch Display Unit LED Panel Microprocessor based Control Unit Reverser BKT Valves Hooter CK1/CK2/CK3
The top portion of CP has sensors and relays connected to the microprocessor unit. The display unit of microprocessor shows working condition of items in engine (electrical equipments apart from engine). The LED Panel displays the overload, auxiliary generator failure, hot engine, rectilinear fuse blown, etc. The battery ammeter shows the charging state of the batteries. REV: Field wiring goes to reverser (REV) and hence it is used to control the polarity of the field which in turn controls the direction of train. BKT: It is a switch which in one direction is used to motor the loco while in other it is used for dynamic braking. Microprocessor based Control Unit: On-board microprocessors control engine speed, fuel injection, and excitation of the alternator. These computers also interconnect with improved systems to detect slipping or sliding of the driving wheels, producing faster correction and improved adhesion. An additional function of the microprocessor is to monitor performance of all locomotive systems, thereby increasing their reliability and making the correction of problems easier. Hooter: It is a vigilance control device (VCD) to keep the driver alert. If the driver isn’t doing anything with the controls for over a minute, the hooter ‘hoots’ and brings the engine speed to the normal speed (low) without asking the driver. It can only be reset after 2 minutes and hence the driver will be held responsible for delay in reaching the next station.
Dynamic braking
It is the use of the electric traction motors of a railroad vehicle as generators when slowing the vehicle. It is termed rheostatic if the generated electrical power is dissipated as heat in brake grid resistors, and regenerative if the power is returned to the supply line. Dynamic braking lowers the wear of friction-based braking components, and additionally regeneration can also lower energy consumption.
During braking, the motor fields are connected across either the main traction generator (diesel-electric loco) or the supply (electric locomotive) and the motor armatures are connected across either the brake grids or supply line. The rolling locomotive wheels turn the motor armatures, and if the motor fields are now excited, the motors will act as generators.
For a given direction of travel, current flow through the motor armatures during braking will be opposite to that during motoring. Therefore, the motor exerts torque in a direction that is opposite from the rolling direction. Braking effort is proportional to the product of the magnetic strength of the field windings, times that of the armature windings. In DLW Locomotives the braking method used is rheostatic, i.e. the traction motors behave as generators (separately excited) and their electrical power is dissipated in brake grid resistors. This method is used for minimising speed of the loco. The loco actually comes to a halt due to factors like air resistance, friction with the rail, etc. 2. Alternator An alternator converts kinetic energy (energy of motion) into electrical energy. All recently manufactured automobiles rely on alternators to charge the battery in the ignition system and supply power to other electrical equipment. Alternators are sometimes called AC generators because they generate alternating current (AC). Electric current can be generated in two ways: The magnet may rotate inside the coil, or the coil may rotate in a magnetic field created by a magnet. The component that remains stationary is called the stator, and the component that moves is called the rotor. In alternators, the coil is the stator and the magnet is the rotor. A source of mechanical power, i.e. the diesel engine turns the rotor. In WDM-3D and WDM-3A locos, the diesel engine’s mechanical output is used to run the shaft of the Alternator. The alternating output of the Alternator is then rectified to DC via solid-state rectifiers and is fed to traction motors (DC) that run the loco wheels. Thus they operate on AC-DC Traction mechanism. WDG4 and WDP4 locos have AC-AC traction with microprocessor control, i.e. AC Traction motors are used thus eliminating the motor commutator and brushes The result is a more efficient and reliable drive that requires relatively little maintenance and is better able to cope with overload conditions.