Document No:
Chapter –14 Locomotive Data
Version No: 1.0-d0
Date Issued: dd/mm/yyyy
Document Title: MANUAL MAINTENANCE FOR DIESEL LOCOMOTIVES
Revised 2013
Printed: 2015/03/08
Page 288 of 303
microprocessor running at 16 MHz with a math co-processor communication through RS-232 serial cable
/ port. EM 2000 controls the main loco functions based on inputs from two traction computers. This
system is equipped with a diagnostic display system in the cab to provide an interface between the
maintenance personnel and the computer. The computer is programmed to monitor and control loco
traction power, record and indicate faults that have been incorporated into EM 2000 system. The Loco is
provided with event recorder, which downloads various parameters for EM 2000 for later use
The loco is equipped with KNORR/NYAB make CCB(computer controlled braking) 1.5 system. This
system is an electro-pneumatic microprocessor based system with 30A CDW type desktop controls. The
overall purpose of using a computer (microprocessor) to control the air brake system is to eliminate as
many of the electrical and mechanical devices as possible, thereby reducing periodic maintenance,
simplifying trouble shooting, fault diagnostics etc. It allows greater reliability and flexibility for future
system upgrade.
These locos are provided with a special feature called blended brake. The purpose of blended brake system
is to maximize the use of dynamic braking. This is accomplished by causing dynamic braking to go its
maximum value whenever blending is requested. Once the amount of asking brake effort is determined,
the maximum amount of dynamic brake effort is determined from the flat top portion of dynamic brake
curve. The amount of dynamic brake effort present at that time, then determines how much air brake
cylinder pressure must be applied to complement the dynamic brake effort. This becomes the air brake
cylinder reference value, which in turn, maintains the asking loco brake effort
Each unit of the Dynamic Brake Grid Blower Assembly consists of fan assembly powered by a 36 HP
series wound DC motor. During dynamic braking, a portion of the current (rectified DC) from the traction
motors is shunted around one of the resistor grids and used to power the grid blower motor. Air driven by
the grid blower drives grid heat to atmosphere.
There are two SIBAS 16 traction control computers. Each computer is dedicated to one inverter. SIBAS
16 is a 16-bit computer based on an INTEL 8086 microprocessor running at 5.6 MHz. The TCC receives
data via RS-485 serial link from the loco computer EM2000. The bi-directional bus carries data such as
how much power for traction the TCC must develop as well as other information to control activation of
devices like blowers and heaters. In addition to the RS-485 data, information constantly gets fed back into
the TCC, to monitor various things such as status of relays and temperature of various components,
voltages and currents. Based on this feedback data and information received via RS-485 serial link, the
programs stored in the TCC work to drive the TCC as well as to protect it in the event of faulty operating
conditions.
The WDG4 loco is equipped with a high adhesion HTSC (High Tensile Steel Cast) truck or bogie. The
bogie assembly supports the weight of the loco and provides the means for transmission of power to the
rails. The HTSC bogie is designed as a powered 'bolsterless unit'. Although the bogie or truck frame itself
is rigid, the design allows the end axles to move or "yaw" within the frame. This movement will allow the
wheels to position themselves tangent to the rails on curves for reduced wheel and rail wear. Axles 1 and 3
can move or kink a little bit to negotiate a curve from 0-8 degree deflection, increases the tractive effort
and improves the rolling resistance. Traction loads are transmitted from the truck or bogie to the loco
underframe through the carbody pivot pin assembly. Each bogie is equipped with three unidirectional AC
traction motors for better adhesion characteristics. The motors are geared to the driving axles, which in
turn apply rotational force to the rails through the wheels. The driving force is transmitted to the bogie
through tractive rod attached to the journal-bearing adapter in the frame. From the truck / bogie frame the
driving force is transmitted to the loco carbody through the carbody pivot pin.
Each loco is an independent power source. Several units may be combined for multiple operation to
increase the load capacity.
The WDG4 loco has been designed on the 'platform' concept which means that the layout and the
mounting of equipment is arranged in such a manner that retrofitment of equipment developed in future on
existing locos as well as equipment changes/upgradation of the existing design of the loco can be
implemented without any major change in the underframe, structure and even layout.
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