| Medha's
Speed Recorders |
|
Medha is one of the leading
manufacturers of Speed Recorders for railway application. These recorders are used on the
locomotives and are similar in function to the Black Box in aeroplanes. These recorders
are used for monitoring the performance of Loco Driver and especially at the time of an
accident the recorded data becomes vital for establishing the cause of accident. The Speed
Recorder is a safety item and hence has to be highly accurate and reliable. |
| Medha designed Speed
Time Distance Recorder Type MRT 912 in 1989. It was an innovative technology in Strip
Chart Recorder, developed as a substitute for the Secheron, Switzerland made mechanical
Speed Recorder used by the Indian Railways then. It was the first microprocessor based
system on the Indian locomotive. The Recorder had many advantages over the imported
equipment: |
|
- It was more accurate due to microprocessor based control
- Reliability was very high and it was maintenance free as the
system was basically electron IC and there were no delicate mechanisms and rubbing parts.
- Cost was much lesser.
|
| Thanks to these reasons. Medha has
become the leading player in the Speed Recorders for Indian Railways. |
|
The Speed Recorder has evolved over a period of
time from the Strip Chart type equipment, where the Recording media was a Wax Impregnated
Chart barely sufficient for 7 days data, to a Memory type equipment where the Recording
media is a Non-Volatile Flash Memory with more than 60 days data capacity. |
| Additional Recording of
critical loco parameters like dynamic braking, coasting, sounding of horn, etc. are also
added in the Memory type Recorders increasing the benefit to cost ratio for Indian
Railways. For AC Locomotives, AC EMUs and DC EMUs the equipment is now supplied with
Energy Monitoring facility, which accurately records the energy consumed by loco in
addition to speed, time, distance and other locomotive parameters. The data recorded in
the Flash Memory can be downloaded onto a PC using downloading software. This software for
data retrieval, analysis and printing is completely menu driven and user friendly. It does
not require any programming knowledge and can be operated with minimum computer literacy.
Medha has designed a totally sealed memory card, with non-contact data transfer and
non-contact power transfer, for electric locomotives produced with ABB technology in
India. |
|
Medha has been in the forefront of all these
advancements and continues to be the market leader for Speed Recorders for Indian Railways
with more than 5,400 Speed Recorders working satisfactorily on Indian Railway locomotives. |
| Microcontroller
based Govenor for Disel Electric(ALCo) Locomotives Type MEG601 |
| The diesel electric
locomotive of Indian Railways was introduced way back in 1964 with technology from ALCO,
USA. Over the years it has become workhorse of Indian Railways. It is a moving powerhouse
with a powerful 16 cylinder diesel engine coupled to a generator capable of producing more
than 3000 HP. |
|
The diesel engine on these
locomotives needs a mechanism to control its speed to run it at different power levels and
speeds, by controlling the amount of fuel going to engine. This control equipment,
popularly known as Governor, was being imported from WoodWard, USA. This is a hydraulic
Governor. |
| Medha has developed an
electronic Governor with totally in house efforts, in its Design Centre, almost 3 years
ago. The equipment was developed with a state of art micro-controller based design and a
stepper motor-based control mechanism. The equipment was designed with philosophy of
modular construction, ease of maintenance, long-term reliability and cost effectiveness.
As the equipment does not contain any hydraulics, it does not require any periodic
maintenance. The equipment, other than performing the main function of governing the speed
of diesel engine as per the commands by driver, also ensures complete combustion of
diesel. This is very important to reduce pollution due to incomplete combustion of fuel
and fuel saving. The equipment is designed with built in fault diagnostic features and
records the errors encountered during running to help the maintenance personnel in
rectifying the problems. The cumbersome procedure of adjustments in hydraulic governors is
eliminated with the provision of simple digital entry of parameters. The design has been
made versatile by providing a number of programmable parameters to adapt not only to
different types of diesel engines but also different operating conditions. The setting of
these parameters has been made very simple by using a PC based menu driven configuration
software, which loads data into the non-volatile memory of electronic Governor even while
engine is running. The equipment is designed to work in the harsh environmental conditions
encountered on the diesel engine like high temperature and continuous vibration. The
equipment was introduced on the locomotives of Indian Railways in 2001. This product is
fast becoming popular with Indian Railways because of its superior performance. |
|
Some of the salient features of Medha's design are 16 bit
Micro controller for fast and accurate control, no hunting from no load to full load
condition, Pollution control by ensuring complete combustion of fuel, on line fault
diagnostics and fault message display, flexibility to adapt to different engines and
operating conditions. |
| Microcontroller
based Locomotive Control System for Disel Electric Locomotive Type MEP660 |
|
The vision of Diesel Locomotive Works, Varanasi
of Indian Railways "to be a world class manufacturer of Diesel Electric
Locomotive" is fully supported by Medha's vision of "to be world leader in
railway products" with the development of microprocessor based locomotive Control
System type MEP660. |
| The diesel electric
locomotives of Indian Railways need a complex control system for controlling operations of
different equipment such as diesel engine, alternator, traction motors and other auxiliary
equipment. With the decision of modernisation of control systems in locomotive operation
by Indian Railways, imported systems from the international suppliers like GE
Transportation, USA initially and later Siemens, Germany, were introduced. Medha took the
challenge of developing such systems. The result of this effort was a
price-value-technology alternative to the conventional system. It was designed and
developed totally in-house by a dedicated team of electronics and mechanical engineers to
make a product that is at par or better than that of international suppliers of these
products. The development effort was not only limited to making a control system but also
spent on building sensors required for application and a real time simulation system. The
simulation ensured that the system is perfected to initiate appropriate actions for normal
and abnormal operating conditions of the locomotive operation. Some of the features
available in Medha's system are not available even in reputed international brands. The
equipment was introduced on the locomotives of Indian Railways in 2002. |
| Medha's Microprocessor
Based Locomotive Control System MEP 660 uses state of art technology, for controlling
diesel electric locomotives. This is a maintenance free alternative to the popularly used
E type excitation system for this application. This provides excitation control,
propulsion control, dynamic braking control, wheel slip control and Auxiliary Generator
control using digital PID controls. This is achieved by constantly monitoring various
analog and digital signals and control the excitation of the Traction Alternator to
maintain constant HP load on the diesel engine. Thermal protection of the traction
equipment, built in fault diagnostic capabilities, fault tolerance, Vigilance control and
Automatic operation of Flasher Lights to enhance the safety of locomotive operation are
some of the features of the Medha's system. A comprehensive display of faults on line and
other information for driver has made the life of driver easy. Fault log with date and
time, event recording and data packs are the functions provided to help the maintenance
staff in rectifying the faults occurred during the Locomotive operation in field. Any
control system needs a setting of parameters to have optimal performance (tuning). The
control system designed by Medha provides setting of parameters through use of PC based
menu driven software making it very simple and user friendly. |
| Introduction of this
system on Diesel Electric Locomotives of Indian Railways is surely a positive step towards
reliable, maintenance free and efficient working of locomotives. Life of the traction
equipment is expected to increase with this control system. |
| Microcontroller
based Control and Fault Diagnostic System for Electric Locomotives Type MCS 654 |
|
Today on Indian Railways, more than
50 per cent of freight and passenger traffic is hauled by electric locomotives working on
25 KV AC Traction systems. A constantly increasing demand due to introduction of more and
more number of trains and demanding targets for freight haulage, has put tremendous
pressure on ensuring increased availability and reduction in the downtime for these
locomotives. |
| These Locomotives are
equipped with a control system to ensure a safe, reliable, trouble-free operation of
various equipment on board. Traditionally the control systems of these locomotives used
relay based control logic to perform the required functions. These control systems, due to
their inherent design, require frequent attention of maintenance staff. In order to reduce
unpredicted downtimes, longer life and reliable operation, a microprocessor based control
and Fault Diagnostic System type MCS 654 was developed by Medha in 2001. The
microprocessor based control system developed by Medha has taken over the function of
these relays and its logic that resulted in considerable reduction in cabling and
interlocking of contacts. At the same time, it has provided the driver and the maintenance
staff, a means to know the exact nature of fault or an error through a Fault log and on
line announcement through a display unit. The system is provided with parameters for
configuration to make it flexible for adapting to various requirements of different
locomotives. |
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