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Prof. S. N. Mahendra is a Professor at the Department of Electrical Engineering at Institute of Technology, Banaras Hindu University. He is better known for his untiring research about Linear Induction Motor Drive for railways. During his working with our institute, he has also taken additional responsibilities including that of IIT-JEE Coordinator (thrice).
Dr. Mahendra has an impressive academic career in the field of electrical engineering. He did his B. Tech. (1970) and M. Tech. (1972) in electrical engineering from our institute and PhD (1976) from City University, London in the field of Current & Flux Densities, Forces & Stiffness in Linear Induction Machines. He has been in the faculty of our institute for over 3 decades. He also served (2003-2005) as Director of NIT Kurukshetra, Haryana. Currently he is Professor and head of the Department of Electrical Engineering at our institute.
Recently, he has been in news media about his proposal to use Linear Induction Motor over conventional Rotary Motor for Metro Railways. Yogesh K. Upadhyaya finds our more about his proposal and research being done at our institute in the subject.
(Please read Campus View section of this chronicle issue for additional information about research being done at our institute, including photos.)
(Prof. S. N. Mahendra)
For bio-data of Prof. Mahendra, please click here.
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Q-1: Please explain how linear induction motor (LIM) works for railways
LIM BASICS
Figure conceptually explains principle of LIM.
A linear induction motor (LIM) is a developed form of its rotary counterpart. Primary member has a three-phase distributed winding. Secondary member usually consists of an aluminum-plate (known as reaction-rail) that is backed by a mild-steel plate for improving the magnetic circuit. When a three-phase current flows in the primary winding, a linear traveling field is produced in the air-gap that interacts with the secondary reaction-rail and develops a linear force much the same way as torque in a rotary induction motor. The linear synchronous speed in LIM is defined as Vs = 2tp.f where tp is the pole-pitch and f is the supply frequency.
Q-2: What is the advantage of LIM drive over rotary motor drive for metros?
The urban transportation problem in cities with population more than one million is becoming dangerously critical. If long-term corrective measures are not taken properly, the transport system of these cities will collapse. In this context Linear Induction Motor (LIM) based transport system has been proposed as a long-term economical and environment-friendly solution of the urban transport problem. The technology of LIM based traction system has been successfully indigenized in Institute of Technology, Banaras Hindu University and has been well appreciated at various levels. Specific advantages will be dealt later. (These will be based on experiences gathered from systems in operation for more than two decades.)
A typical blue-print for adoption of this technology for solving urban transport problem may include following objectives to develop and standardize methodology/technique:
1. Survey of existing ground conditions.
2. Excavation process and equipment selection.
3. Design of terminal and platform.
4. Track design.
5. Design of Linear Induction Motor and Reaction Rail.
6. Design of current collection, control system and controller.
7. Conducting studies related to Socio-economic impact analysis of the proposed system
8. Organize seminars for generating information listed above and bridging the perception gapes between technology, its implementation and the users.
Q-3: Where the LIM technology is in use for railways? Why it is not popular yet compared to rotary drive?
LIM technology is being primarily applied in metros with advantage. At international level activities related to development of LIM based transport system have been going on for quite some time. Bombardier Inc., Canada, & Japanese Subway Association, Japan, have achieved effective breakthrough by implementing the technology to urban transport system. Salient points related to experience of these organizations is given below.
JAPANESE SUBWAY ASSOCIATION
1. Adopted in March 20, 1990
2. Track length 15.0 km covering 17 stations.
3. System with 1200 cars realises 3-minute headway for 4-car operation and carries about 2.7 million passengers daily.
4. Line is essential means of transportation as it connects business districts & suburban residential areas approximately 30 minutes away.
5. Lowered bogie floor reduced tunnel cross-section by 40%; length, width and height of subway cars by about 3 m, 0.3 m and 0.7 m respectively and total estimated construction cost by 20%.
6. 100 kW naturally cooled LIM mounted on each bogie.
7. Reaction rail (360-mm wide, 5-mm thick aluminum-plate & 22-mm thick iron-plate) fixed to the sleepers along the rails.
8. Accelerating/braking-force & LIM speed controlled by inverting overhead centenary 1500 V D.C. to 3-phase VVVF a. c.
Salient Features of Tokyo Metropolitan Subway Line 12
1. Second Japanese Linear Metro. Established in December 1991. Extended in 1997 & 2000.
2. Track length 12.9 km with 12 stations. Proposed track length 27.8 km with 26 stations.
3. System has 124 cars for 8-car operation to realize a 5-minute minimum headway.
4. Power supply is through 1500 V D.C. catenary.
5. Subway Line 12 links busy areas in the heart of Tokyo via an underground loop and carries one million passengers a day.
Japanese Field trial Experiences
1. For gap length 10mm to 13mm, gap-variation observed 3mm.
2. Acceleration (7-10%) deceleration (6-9%) higher for 10mm gap as compared to 13mm gap.
3. 4% less electric consumption for 10mm gap than for 13mm.
4. Insufficient rail greasing increased wave-like-pattern wearing of the rail surface & left-right swinging of trains. With sufficient rail greasing rail corrugation was prevented & wave-like-patterns of wearing disappeared.
5. Tokyo Metropolitan Subway Line 12 was possible due to Linear Metro's advantages like ability to handle sharp curves & steep gradients (as existing subway and train lines did not permit new lines due to serious limitation of space availability).
BOMBARDIER INC. CANADA
· Bombardier Inc. has been the world leader in applying LIM technology to urban transport system. First revenue service started in 1984.
· Major user of LIM, the British Columbia Rapid Transit Company (also operator of Vancouver SkyTrain) reports great satisfaction.
· Canadian consortium bid (headed by Bombardier Inc., SNC-Lavalin and BC Transit) for supply of LIM based advanced LRT system MK II for Kuala Lumpur, Malaysia, selected against rival bids of France, Germany & Japan offering rotary motor based systems.
· Consortium’s bid was for supply of 70 ART MK II vehicles with LIM propulsion & steerable suspension to provide service for 24-stations spread over 29 km (4.4 km tunnel, 2.11 km at grade & 22.27 km elevated). Phase I made operational during the Commonwealth Games in 1998. Present 10,000 pphpd (Pallets per hour per direction) capacity can accommodate designed 30,000 pphpd.
Operational experiences
1. Mechanical failures from debris or insulation failures are negligible.
2. Maintenance of LIM limited to occasional blowing out of dirt from the end windings. No need for inspection or overhaul of gearboxes or couplings.
3. Trucks made lighter than the conventional subway trucks.
4. Axles of steerable-axle truck steer with the track curvature. Thus, almost eliminating flange-contact with the rails; reducing objectionable-noise found with fixed-axle trucks; improving ride quality; increasing wheel-life and reducing truck-maintenance
5. Wheels machined after 1Lakh km. Removing 1mm to restore optimal conical profile, thus wheel-life is about 10 Lakh km.
6. Wear rate of disc brakes very low as LIM provides almost all the braking.
7. Braking overshoot does not occur and train performance is repeatable. Headway reliability thus is above 98% (at 3 minutes headway operation).
8. SkyTrain per-unit energy-consumption cost same as Toronto subway.
9. LIM ALRT success suggests its suitability for conventional transit operation. Hence issue is not technical but economical.
10. After twenty years of service the selection of LIM traction to meet the performance and operational requirement remains the proper choice.
11. Observation in favour of LIM propulsion negate criticisms like ‘Technology is not proven’, ‘Efficiency is lower than DC motors’, ‘air gap would be a serious maintenance problem’ and similar more.
12. Bombardier Inc. appreciation of LIM based traction has special significance, as it is a supplier of both rotary steel-wheel-on-steel-rail (Ankara Metro & London Docklands Light Railways) and LIM automated system.
As regards answer to the question ‘why is it not popular yet compared to rotary drives?’ – Partly the Question has been answered in point 11 above. In addition, the other main reason perhaps is that there is a technology-appreciation-gap between the merits of the technology and the decision makers.
Q-4: Please describe the research work on LIM being done at our institute.
BHU has been working on LIM based propulsion working systems for more than 3-decades starting from:
• shuttle-propulsion for weaving looms (1971-73)
• surface-transport (1980 continuing)
• overhead-transport (1983 continuing)
• Conveyor-belt/material handling (1986 continuing)
• testing-methodologies & test-rigs (1980-87)
• design & analysis methodologies standardization (1973-97)
• Malaviya Center LIM metro system (1997 continuing)
• Independent control of forces of propulsion & attraction (2003 continuing)
Few working systems developed in IT-BHU
IT-BHU over the three-and-half-decades has pioneered and indigenously developed Linear Induction Motor (LIM) based traction technology for solving the urban transportation problem of Indian cities. A LIM based demonstrative system in the Malaviya Center for Development of Low Cost LIM Propelled Metro at IT-BHU is operating since 1999 along a 60-meter Meter-Gauge track and carries 15-20 adults.
The R&D has reached a stage when it has become necessary that related and supportive expertise already available at national level be integrated with the Linear Induction Motor (LIM) based traction technology developed at IT-BHU by adopting a consortium approach. If required, expertise available at International level may also be integrated suitably.
For additional information about research being undertaken at our institute, more discussion about LIM technology, photos, etc. please refer to Campus View section in this issue of Chronicle.
Q-5 Does the Project have any commercial application
The increasing explosion of population, industrialization, decrease of useable-land have compelled the scientist, technologist, planners, designers and government organization to search an alternative which is economical and eco-friendly both. The cities having population more than one million are eligible for underground metros, as most of these cities do not have any scope for:
- Widening of the existing roads (as this process is already saturated)
- Use of an over-head transport system (due to narrow roads)
For this reason there appears to be no other alternative except to go for effective and safe utilization of underground technology.
The Project has commercial application because underground metro, in the present situation, is the best solution for the urban transportation problem of Indian cities. The outcome of the project has good export market also because problem of urban cities in other countries is no different than that in India. The underground urban transport system is sustainable and safe mode for transportation. It will save:
- The city from pollution,
- The commuters from health-hazards & wastage of travel-time.
Q-6:
The question now arises ‘Can LIM technology be developed indigenously?’
The answer has been best given by Late Shri J. Upadhyay, Former Member Railway Board, Visiting Professor & Advisor AICTE project entitled LIM Propelled Rail Metro System at I.T. - B.H.U. and the answer (Upadhyay 1999) has been reproduced below:
“Indigenous development of any technology reduces the overall initial and recurring costs drastically. It has been our experience in Indian Railway that an indigenously developed electric locomotive or its subsystem cost approximately 30-40% of the imported version. Hence it is relevant to dwell upon this aspect in some detail.
a) The test setup at IT-BHU, which perhaps is the first of its kind in this country in the context of a new technology, was developed locally including design of the LIM. The various track-related parameters have remained reasonably stable without much maintenance. Hence we may reasonably infer that design of the LIM and most of the subsystems can be done with the available expertise if pooled on all India basis. It may be necessary to borrow from the expertise developed abroad in same critical areas e.g. rolling stock, steerable bogies & VVVF control strategy, to shorten the over-all time frame.
b) Therefore, further development of this technology will call for formation of a consortium at the national level consisting of user ministries, public sector manufacturing companies including Railway workshops and technical institutions.
It must be clearly understood, that LIM rail-metro is a proven and cost-effective technology as borne out by the experience of LIM metros in Osaka and Tokyo. It is for us to recognize its virtues and do away with our reservations so as to achieve self sufficiency in this field of advanced technology by pooling resources available within the country through a consortium approach. This is in line with the strategy adopted even in advanced countries.”
Justification for indigenous development of LIM based traction technology in India
- At a later date if this technology is imported, we will not only pay for equipment and technology but also the developmental cost.
- In fact, the supplier of the equipment and technology will be gaining experience at our cost whereas we will remain ignorant even after paying for it.
- Furthermore, we will remain dependent on the supplier for any modification or up-gradation of the technology in future as it is happening in almost all the technology transfers.
Q-7: Please tell us more about yourself.
I was born in Khairabad (Dist. Sitapur) UP, India in 1949. My school and college education was done at Lucknow. I studied at Loreto Convent and Christ Church School. Then after, I joined Kanyakubi College and Colvin Taluqdars’ College. After passing Intermediate College exam by UP State Board in 1966, I joined IT-BHU for Electrical Engineering, where I obtained B. Tech. and M. Tech. degree in electrical engineering. Later on, I did my PhD in electrical engineering from City University in London. After returning to India, I have been teaching in the department of electrical engineering at our institute; except for few years, when I was appointed as Director of NIT, Kurukshetra.
I am involved in activities of various technical societies and have been awarded as Fellow of Institution of Electrical Engineers (FIEE) U.K.
My family includes my wife Chhaya and children Ankur and Pallav. My hobbies include Reading, watching TV, etc. My life philosophy is to live a life by integrating one-self with nature in perfect harmony for happiness on Man & his environment
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Prof. Mahendra can be reached at: mahendra20@gmail.com
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Additional Links
1) LIM system better than the one used in Delhi Metro
http://www.hindu.com/2008/11/18/stories/2008111852510300.htm
2) LIM system better than used in Delhi metro: BHU Prof
http://www.zeenews.com/states/2008-11-16/484072news.html
3) News in Hindi-Development of cheaper metro rails
http://in.jagran.yahoo.com/news/national/general/5_1_4994170/
4) Funakawa Information & Environment Technology Co., LTD.
http://www.funaken.net/result01_en.php
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Philosophical difference between REM based & LIM based Traction - A Historical View
Primitive Transport: Carrying and Dragging
Green: Minimum Friction desired.
Blue: Pull from pull-producer to pull-receiver
Red: Adhesion which is essentially desired in all types of transport systems between driving wheel and the facing stationary surface. However in LIM systems the LIM is used as pull producer and therefore all the wheels are only rolling wheels.
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Mr. Devender Singh Maun (Ceramic 2nd year) is best known for his invention of unique water filter. The equipment, known as ExVirus, has the tremendous potential of use for providing purified water to rural population at low cost and without the need of electricity.
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We are pleased to publish interview with Mr. V. K. Menon, who is Senior Director - Careers, Admissions & Financial Aid at Indian School of Business, Hyderabad.
The interview was planned so as to gather relevant information about this institute directly from the institute’s administration. We have been approached by some of our students/alumni who are interested in pursuing MBA study from premier institutes in India, to provide them with more first-hand information about the institute, admission procedure, financial aid available, etc. Moreover, every year some of our students and alumni join ISB for MBA.
Yogesh K. Upadhyaya from chronicle discusses with V K Menon to find out more about ISB and what it has to offer:
(Mr. V. K. Menon, Senior Director, ISB)
Q-1: Welcome, Sir. Please tell us about ISB.
The Indian School of Business is a premier management institution established in 2001. In a short span of seven years, the ISB has successfully pioneered several new trends in management education in India and has established itself as a leading B-school across the world. The last ranking of Global B Schools done by the Financial Times, London, places the ISB at the 20th rank across all B Schools. In both its Post Graduate Programme (PGP) in Management and Executive Education Programmes, the ISB invites high calibre international faculty from reputed B-schools across the world to teach and participate in collaborative research along with the strong pool of research oriented, resident faculty at the ISB.
Beginning with an intake of 129 students in 2001, the first year, the ISB will now be admitting 560 students for the next batch PGP. This is the fastest ramp up of a business school in any part of the world.
The ISB has academic associations with the Kellogg School of Management, The Wharton School, and the London Business School.
Every year thousands of students apply to ISB among which are a bright lot who are alumni of the IT-BHU. This year too we have over 10 students who are alumni of the IT-BHU and have made it to the batch through the tough competition.
Q-2: We understand that the ISB has multiple programmes on campus including a very strong Executive Education Center. What is your Flagship programme?
Our Full Time Post Graduate Programme (PGP) in Management is our Flagship programme and offers multiple learning opportunities in a short span of one year. Specially designed for professionals with work experience, our learning model covers a broad ground with case studies and real life projects. The average work experience of the current class is 5 years. They have been working in various countries across the world in premier companies prior to joining. Through interactions with faculty, business leaders, peers, and alumni, the students benefit personally and professionally.
After the programme, the students are placed in the best of companies in India and abroad. Last years recruitment saw the students being placed in 23 countries. 230 companies participated in the campus placements programme. The average domestic salary was INR 1.9 million and the average international salary was 144,812 USD.
Our Centre for Executive Education (CEE) offers a large range of executive education programmes for senior management. With a faculty drawn not only from the ISB but from some of the world's leading management institutions the education delivered is of world class standards. The CEE strives to provide expert advice and guidance to all participants utilising its unique provisions to draw on skills from faculty across the globe.
Q-3: Please tell us about the faculty for the PGP.
Our faculty includes eminent management intellectuals with research and teaching experience from the best B-schools in the world. The distinctive research of our faculty members ensures that the programme offers content that is contemporary and global in its perspective.
With an ideal mix of resident and visiting faculty, provide the benefit of a strong research base and international exposure. Visiting faculty from Wharton, Kellogg, London Business School, Cornell, Chicago, Duke, and UCLA, among others, teach at the ISB. With the School gaining international recognition, many research scholars from around the world visit the ISB on long-term sabbaticals. You have the opportunity to gain from an exchange of ideas with them.
Q-4: What is the kind of infrastructure do you have on campus?
The ISB’s world class campus provides students an ideal environment. The Academic Centre houses an extensive library, air-conditioned lecture theatres, a computer centre, meeting rooms, and an auditorium. The lecture theatres are equipped with a broadband communications network that ensures global connectivity. You can interact by computer or video-link with faculty, industrial leaders and other students anywhere in the world. Audio-visual and video conferencing facilities like overhead projectors, LCDs, fixed cameras and touch-pad systems make the learning process much more convenient, interactive, and enjoyable.
The heart of the academic block is the library known as the Learning Resource Centre (LRC) that supports the ISB in building an internationally top-ranked research driven management institution. You can have direct access to various printed and electronic information resources. The LRC also provides innovative and responsive services to meet the changing needs of the academic community.
Comfortable residential facilities are available in the Student Villages. Families can stay in air conditioned studio apartments. Single rooms are provided in four bedroom apartments. All of them are serviced, air-conditioned, fully furnished and equipped with a cable connection, voice and data ports for telephone, campus LAN and the Internet.
Recreational facilities like a swimming pool, gym, courts for various games help you stay fit in spite of your busy schedule. Every need– dining, laundry, housekeeping, and banking- is taken care of allowing you to focus exclusively on making the best use of your time here.
We strongly believe that people seriously interested in taking up the PGP should visit the campus to witness our infrastructure before applying.
Q-5: What are the selection criteria for admission?
To be eligible to apply, you need:
- A Bachelor’s degree
- A valid GMAT Score
- Preferably 2 years of full-time work experience
The ISB seeks demonstrated initiative and leadership potential, consistently good academic performance, strong communication skills, team playing and other participative learning skills in prospective applicants.
A GMAT score helps us in assessing suitability to the programme. We do not have a cut-off GMAT score. While a good GMAT score helps, an average score can be compensated for by achievements in other areas.
Q-6: What is the cost involved and financial aid available?
The cost for tuition would be around USD 40,000. There are more than 100 scholarships offered by the ISB. This is over and above the scholarships that are offered by various premier organizations.
Loans are available at very competitive interest rates for those students who are admitted to the program. Repayments are flexible and the repayment period can be decided by the student.
Q-7: How does 1 year MBA program at ISB compares with 2 yr programs at other institutes? Why should a student prefer ISB over other institutes?
The ISB’s one year programme in management is ideal for working professionals to enhance their career without a long hiatus from work. The programme is rigorous and challenging, but it encourages learning beyond classroom instruction. You learn not just from the faculty and your peers, but also from successful leaders and entrepreneurs who frequently visit the campus.
You are able to get back to work quicker. You save the opportunity cost of one year (you earn post ISB salary for the second year). Hence you recover your investment much quicker.
It is a high intensity program, as the contact hours of this programme are almost similar to that of a two year one. At the ISB you have 680 contact hours compared to the 700-720 of a two year programme.
The intensity of the programme teaches you to analyse situations quickly, to think on your feet and to apply your skills to real business situations. You learn to combine your industry expertise with the fundamentals of management that you acquire over the year. With the one year management programme you can not only minimise career interruptions, but also effectively recharge and equip yourself for an exciting career ahead.
Companies also encourage their high- potential employees to pursue one year programmes to prepare for leadership roles. In addition to all this, a one-year programme has a great advantage over a two-year programme because of the tremendous savings in opportunity costs.
Q-8: Please tell us about yourself.
I did my Electronics and Communication Engineering from REC Tiruchi ages back – in 1976 and then PGDM from IIM B – in 1982. I worked in industries such as – Nelco, ECIL, Philips, Escorts and BPL US West Cellular Ltd. This was for 18 years. I was Head – Sales Marketing and Service Delivery at BPL US West, for Kerala and National Sales and Service Manager, for Escorts Communications Ltd. I then moved over to Academics. Taught and researched in Marketing at the SDM-IMD, a good B School in Mysore, before moving to the ISB in 2004.
Right now, I manage, Careers, Admissions and Financial Aid here, as Senior Director. Anytime you feel like playing a game of Badminton, Billiards, Chess or Bridge, - drop in.
Thanking you, sir. We hope information provided by you will be useful to our readers.
To contact Mr. V. K. Menon, email: PGPadmissions@isb.edu
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Additional links:
Prospective Students: http://www.isb.edu/intermediatepages/Prospectivestudents.Shtml
ISB campus, Hyderabad (Courtesy skyscrapercity)
Institute of Technology, Banaras Hindu University
Varanasi 221005, UP