Seminar report ..)

1. The Inductrack: A Home-Grown Maglev System for our Nation Lockheed Martin Palo Alto Colloquium Presented by: Richard F. Post, Lawrence Livermore National Laboratory 15 Apr 2004 Lock./01

4. The German Trans-Rapid maglev train is an EMS system using electromagnets attracted to an iron “rail” Lock/04

5. The German Trans-Rapid maglev train uses powered electromagnets attracting upward to an iron rail Lock./05

6. The Japanese Yamanashi demonstration maglev train uses superconducting magnets on its sides Lock./06

7. At speed superconducting magnet coils on the Japanese train induce currents in coils in the “tracks” on each side Lock./07

8. An EDS Urban Transit Maglev system test track and test car has been built and operated in Korea Lock.1/08

9. The proposed “Swiss-Metro” would link major Swiss cities by maglev trains running in evacuated tunnels . Proposed in 1974, and under study since 1989, the Swiss-Metro system would carry 200 passengers in train cars running every 6 minutes. The trains would operate in tunnels evacuated to 1/10 atmosphere (atmos. pressure at Concorde flying altitude ). Lock./09 Contactless energy transfer system Linear electric motor and guidance system Magnetic levitation inductor Emergency pavement Emergency guidance And braking system

14. Klaus Halbach 1925-2000 Klaus Halbach, good friend and kind mentor, died on 11 May 2000. Lock./14

15. Fields of the in-between permanent-magnet bars add to the field of the adjacent bars below and cancel above Lock./15

16. The moving Halbach array magnets induce currents in the close-packed shorted circuits embedded in the track Lock./16

17. One possible configuration of the Inductrack is the magnetic equivalent of the flanged wheels on a train Lock./17

18. The levitating force becomes effective at very low vehicle speeds and remains constant at high speeds Lock./18

19. The Lift-to-drag ratio of the Inductrack increases linearly with speed, and can exceed 200 at maglev train speeds Lock./19

20. Our Inductrack model car is launched by pulses from a series of electronic circuits Lock./20

22. Ferrite “tiles” add inductive loading for our model Inductrack, reducing the transition speed. Lock./22

24. The cradle is fabricated from high-modulus carbon-fiber composite to maximize rigidity and minimize weight Lock./24

25. The levitated cradle surrounds the “track” that is composed of levitation coils and interleaved drive coils Lock./25 Guide rails to prevent magnets from hitting track prior to levitation One of 6 magnets (3 front, 3 back) that provide levitation and centering forces Steel box beam Drive & levitation coils in track C-fiber cradle with ribs to support magnetic force Fiberglass I-beam

26. The NASA model track is made up of modules that are composed of 13 interleaved drive and levitation coils Lock./26 D r i v e C o i l # 6 G A M a g n e t W i r e 4 1 C o i l A s s e m b l y : 1 3 D r i v e a n d L e v i t a t i o n C o i l s L e v i t a t i o n C o i l # 1 0 G A M a g n e t W i r e D i m e n s i o n s i n c m T o l e r a n c e + / - 0 . 0 5 5 6 5 1 2 1 5 Support blocks that attach coils to rail

28. The levitation and drag forces of the Inductrack can be analyzed using circuit theory and Maxwell’s equations Lock./28

29. To analyze the Inductrack we start with the equations for the magnetic field components of a Halbach array B r = Remanent field (Tesla), M = no. of magnets/wavelength. d(meters) = thickness of Halbach array magnets, k = 2π /  Lock./29

30. Integrating B x in y gives the flux linked by the Inductrack circuits and yields equations for the Lift and Drag forces w = width of Halbach array, L,R = circuit induct./resistance Newtons/circuit Newtons/circuit Lock./30

31. Dividing < F y > by < F x > yields an equation for the Lift-to-Drag ratio as a function of the track circuit parameters . The Lift/Drag ratio increases linearly with velocity, and with the L/R ratio of the Inductrack track circuits . Lock./31

32. The levitation efficiency (Newtons/Watt) can be determined directly from the equation for the Lift/Drag ratio Newtons/Watt Typical K values: K=1.0 to 5.0, depending on track design Lock./32

34. A “ladder track” can be constructed using litz-wire cables encapsulated in thin-wall stainless-steel tubes Cable ends soldered Into shorting bus bars The use of “braided” litz-wire in the cables assures current uniformity and minimizes parasitic eddy-current losses Lock./34

35. The laminated “ladder track” is a high-efficiency, cost-effective, alternative to the litz-wire ladder track Lock./35

37. Photo of LLNL Laminated-Track Test Rig Lock./37

38. There is good agreement between the LLNL code predictions and the Inductrack test-rig measurements The code predictions are shown for zero and plus and minus 1.0 mm displacements Track: 15 laminations of 0.5 mm thick copper sheet. Slots: 15 cm. long, 0.25 mm. wide. Conductor strips 2.5 mm wide. Lock./38

41. Adjusting the relative height of the Inductrack II Halbach arrays optimizes the levitation force vs drag power Lock./41

42. Inductrack II Lift-to-Drag Ratios • The L/D for Inductrack II systems is much higher than for Inductrack I Inductrack I Inductrack II Guideway parameters (both cases): 2.0 cm. laminated copper, p.f. = 0.9 Lock./42

43. Vehicle on Guideway Linear Synchronous Motor Suspension Track Double Sided Magnet Array The General Atomics urban maglev system employs The Inductrack II dual-Halbach-array configuration Lock./43

44. A full-scale levitation/propulsion test track is nearing completion at General Atomics in San Diego Lock./44