DIESEL-ELECTRIC LOCOMOTIVES: TRACTION ASSEMBLY AND LOCOMOTIVE TESTING
I take this opportunity to express my heartfelt gratitude to the entire DLW team who helped me understand the basics of locomotives. I acknowledge with thanks the help extended by my project guides, Mr. N.N. Pathak (LTS) and Mr. Nizam (TAS). I am also very grateful to the many individuals, esp. Mr. U.C. Tiwari (Electrical Division) who offered me ideas, contacts and support along the way.
1) ABOUT DLW (DIESEL LOCOMOTIVE WORKS) 4
2) LOCOMOTIVES PRODUCED BY DLW 5-7
a) BROAD GAUGE MAIN LINE FREIGHT LOCOMOTIVE: WDG 3A
b) BROAD GAUGE MAIN LINE MIXED SERVICE LOCOMOTIVE: WDM 3D
c) WDG4 - 4000 HP GOODS LOCOMOTIVE
d) WDP4 – 4000 HP PASSENGER LOCOMOTIVE
3) TAS: TRACTION ASSEMBLY SHOP 8-11
a) CP (CONTROL PANEL)
c) TRACTION MOTORS
d) 16 CYLINDER DIESEL ENGINE
e) MASTER CONTROL
g) AUXILIARY GENERATOR & EXCITER
i) CRANK CASE EXHAUSTER
j) MECHANICAL ASSEMBLY
4) LTS: LOCOMOTIVE TESTING SHOP 12-13
b) AN OUTLINE OF LOCO TESTING
5) INNOVATIONS IN GLOBAL LOCOMOTIVES 14
a) WHY DIESEL-ELECTRIC LOCOS?
b) RECENT TRENDS
6) REFERENCES 15
ABOUT DLW (DIESEL LOCOMOTIVE WORKS) ORGANISATION[/b] A flagship production unit of Indian Railways offering complete range of products in its area of operation with annual turnover of over 2124 Crore. State of the art Design and Manufacturing facility to manufacture 200 locomotives per annum with wide range of related products viz. DG Sets, Loco components and sub-assemblies. Supply of spares required to maintain Diesel Locomotives and DG sets. Unbeatable trail-blazing track record in providing cost-effective, eco-friendly and reliable solutions to ever increasing transportation needs for over four decades. Fully geared to meet specific transportation needs by putting Price - Value - Technology equation perfectly right. A large base of delighted customers among many countries viz. Myanmar, Sri Lanka, Malaysia, Vietnam, Bangladesh, Tanzania, Angola, to name a few, bearing testimony to product leadership in its category. Staff Status in DLW (As on 1st Oct'2009) Total Staff in DLW 5974,Production Staff 2362
MILESTONES Transfer of Technology Agreement DLW entered in an agreement with General Motors of USA (now EMD) for technology of transfer to manufacture high horse-power 4000HP AC-AC GT46MAC and GT46PAC locomotives in India making India the only country outside North-America to have this leading edge technology. Returns from Transfer of Technology First PKD WDG-4 locomotive turned out in August 1999. First DLW built 4000 HP *WDG-4 Freight loco turned out in March 2000. First DLW built 4000 HP WDP-4 loco turned out in April 2002. Locomotive design projects WDG4 locomotive with IGBT base TCC (Siemens & EMD) turned out. Indigenous AC-AC control for WDG4 (with distributed power controls) Indigenous AC-AC control for WDP4 (with hotel load capability) WDP4 locomotive with IGBT base TCC & Hotel load capability.
*Note: Nomenclature (Naming) of DLW Locomotives: D → Diesel Type W→ Wide (width of gauge) G→ Goods P→ Passenger M→ Multipurpose x→ Any numbers in the name represent the horsepower (hp=x×1000) A→ 100 hp B→ 200 hp C→ 300 hp ; and so on... Hence WDG-3A stands for Wide Diesel Goods- 3100 hp engine & WDP-4 represents Wide Diesel Passenger- 4000hp
TAS: TRACTION ASSEMBLY SHOP TAS is the unit in which all the locomotive parts are assembled, that include:
1. CP (Control Panel)
3. Traction Motors
4. 16 cylinder Diesel Engine
5. Master Control
7. Auxiliary Generator & Exciter
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.
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.