1. Chandan Kumar2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China

2. INTRODUCTION Linear Induction Motor (LIM) is the linear form of rotary Induction motor . It transform the electromagnetic energy to translational motion withoutusing any gear mechanism. LIM is used for machine tools, linear tables, textiletools, saws, separators, transportation systems .and many others.2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 3. MODEL DEVELOPED IN IRIEEN,NASIK The project has been an extension of the AICTE project in the department ofElectrical Engineering, IT BHU. All the experiments were performed over a live practical model of LIMP Metro TrainSystem at Indian Railways Institute of Electrical Engineering, Nasik. It is a 3 phase,4 pole,33 slots,H class insulated with length of .583 m,width of.132m and height of .062m. Ratings :600V,15 A,50Hz,52.4 Km/hr 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 4. Static Test And its Important It helps in the study of starting characteristic of Linear Induction Motor. Static test result is used for determining the voltage and frequency response of the LIM at standstill and it will help in selection of the electrical drive for starting andcontrol of LIM for traction purpose.Various tests that were performed to simulate practical situations are undermentioned:1. Constant V/f control testing by changing air gap between primary and secondary for different V/f ratios.2. Tests conducted by de-aligning primary with respect to secondary .3. Tests performed by creating breaks in the secondary circuit of LIM. The breaks are created in the electrical circuit and magnetic circuit independently as well as simultaneously.4. Voltage control testing for constant frequency of 50 Hz2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 5. V/f control test The tests were carried out for V/f ratios of 6, 8, 9 and 10 each under 3 different airgaps of 9mm, 7mm and 5mm using ACS 600 VVVF Drive.Propulsion Force variation with frequency for different V/f Input Power variation with frequency for different V/f for 9mm airgapfor 9mm airgap 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 6. Results of V/f control test For best starting, V/f control should be done starting at 25 Hz in order toavoid initial saturation due to voltage boost up. Air gap of 7 mm was found to be the optimal for system considered. Airgap of 5mm is very tough to achieve . Airgap of 9mm lead to reduction in the force which makes them notsuitable for our system2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 7. De-Alignment Test The de-alignment tests are carried by de-aligning the LIM primary with respect tosecondary in lateral direction . 11 %( 15mm) and 25% (32 mm) de-alignment of primary with respect to secondary wasobserved on the Propulsion force and input Power for V/f ratio 9 with airgap of 7mmInput Power variation with frequency for De-Propulsion Force variation with frequency for De- alignment and reference value alignment2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 8. Results of De-alignment test Up to 25% de-alignment the propulsion force developed is quite healthy comparedto reference . The Input Power Variation is small with the lateral shift. So we can go up to 25% de-alignment for practical application like traction. For traction application the turns will be slightly affecting the LIM but give a goodperformance inside the tolerance limit. 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 9. Test by introducing break in secondary circuit1. By creating breaks in Electrical circuit by using discontinuous aluminium: 9.7cm, 20cm and 32.4cm.Propulsion force vs. Frequency for Al Breaks Input power vs. Frequency for Al Breaks 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 10. Test by introducing break in secondary circuit ..2. By creating breaks in Magnetic Circuit by using break in the mild steel (Back Iron): 5.2cm, 11cm and 19.5cmPropulsion force vs. Frequency for Mild Steel BreaksInput power vs. Frequency for Mild Steel Breaks 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 11. Test by introducing break in secondary circuit ..3. Simultaneous breaks in electrical and magnetic circuits: 6.2cm and 17.5cmPropulsion force vs. Frequency for reaction rail breakInput power vs. Frequency for reaction rail break 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 12. Results of Break test As the Electrical circuit break length increases the magnitude of propulsion forceget reduced sharply. This behavior can be accounted for reduced eddy current dueto absence of electrical circuit. This weakens the strength of poles developed onsecondary. The reductions in propulsion force due to break in magnetic circuit is not asdominant as due to break in the electrical circuit. Large break in electrical circuit is not desirable as it reduces the propulsion forcegreatly. Large breaks in magnetic circuit (up to 30% of length of LIM primary) can beallowed wherever required Even 10 % of simultaneous break in the Aluminium and Mild-steel cause largereduction in the propulsion force2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 13. Voltage Control Test Voltage control tests were carried out at constant frequency of 50 Hz. The voltage was varied from 207 volt to 500 volt using the VVVF drive. Data were obtained for three different air gaps of 9mm, 7mm and 5mmPropulsion Force variation with voltage for different airgap Input Power variation with voltage for different airgap 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 14. Results of Voltage Control Test If the starting will be done at rated voltage or if high voltage will be appliedto obtain large starting torque, it will cause saturation of mild steel core ofLIM. So, constant V/f control gives a better solution where starting can be doneat lower frequency and hence higher starting torque can be obtained atwide range of initial speed.2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 15. CONCLUSION This paper has investigated Static performance characteristics of a single sided LIMfabricated to drive a LIMP Metro Model developed at IRIEEN, Nasik, under standstillcondition. Experiments were performed by developing a static test bed on the testing track. The results obtained from the test supports the advantages of application of LIM inmodern metros. It will help in carrying out the further investigation in starting of LIM based drive.2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 16. ACKNOWLEDGEMENT ICCEE 2010 for giving us a opportunity to present our paper at the seminar. Dr. S. N. Mahendra for his valuable support and guidance during design, fabricationand planning of these tests. Mr.V.K.Dutt, Additional Member Electrical Railway Board, Indian Railway for hisinterest and making it possible for him to work in IRIEEN, Nasik. Mr.D.Ramaswamy, Director, IRIEEN and all the professors of Indian railway Instituteof Electrical Engineering, Nasik. Raj Kumar Sinha, Pritesh Kumar, Rajeev Sisodia and Ram Gopal Varma for theirconstant help and support in carrying out the experiment. 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 17. BIBILIOGRAPHY Mahendra S.N; Reports of AICTE funded Project on LIM at IT BHU,1994-99 Mahendra,S.N.;LIM based traction:philosophy,selection,design aspects andapplicationto transport sector,International Workshop on LIM propelled rail MetroSystem,Banaras Hindu University,Varanasi,India,Jan 8-9 1999 Yunhy-un. Cho; An Investigation on the Characteristics of a Single-sided LinearInduction Motor at Standstill for Maglev Vehicle. IEEE Transactions OnMagnetics, Vol. 33, No. 2, March 1997. Upadhyay,J.,Mahendra,S.N.;EleectricTraction,Allied publishers Ltd.,NewDelhi,2000 2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China 18. Thank You chandan.kumar.eee07@itbhu.ac.in2010 3rd International Conference on Computer and Electrical Engineering,Chengdu,China