Building an 8-foot wind turbine Brent Summerville Appalachian State University

1. Building an 8-foot wind turbineBrent SummervilleAppalachian State University

2. Backhome Magazine article www.backhomemagazine.com www.otherpower.com …derived from Hugh Piggott’s axial flux plans or “How to build a wind turbine” Go with the source and follow plans closely Research: In search of Plans

3. Workshops in Washington, Scoraig, CAT, Edinburgh, Ghana, France, Costa Rica, Liverpool….. This is Jay from France. He also came to a Beech Mountain workshop. Research: Hugh Piggott

4. Sat in on Intro to Wood Technology Trained on techniques, tools, machinery and safety Practice…Sanding block, cedar tool box Last semester for Bill Hanner Resources: Woods Lab • Draw knife • Hand plane • Spoke shave • Lathe • Jointer • Sanders • Gluing panels • Planer • Bandsaw • Drill press • Table saw…

5. Sat in on Intro class Trained on techniques, tools, and machinery Copper nameplate, dinner bell, apple butter stand Nice working with Leo and Dave Resources: Metals Lab • Welding • Mill • Lathe • Plasma torch • Blacksmithing • Grinding • Tapping • Sheet metal fab • Drill press • Iron worker…

10. Basswood with termites Bladecarving Layout Thickness, width, length Check, carve, sand… Carve with draw knife and spoke shave Sand, sand, sand

11. Jointer, planer, table saw, and belt sander to form 1-1/2”x6”x52” blanks Finished length is 48”. Keep long until finished carving. Makes for a nice blade tip.

12. Start with a precise layout

13. Simple tools

14. Carve the taper with the drawknifeClamp and sand to keep the blades matched

15. Carve the twist and check the drop

16. The drawknife can remove a lot of material quickly, and it’s a good workout Carve the thickness

17. The spoke shave is pleasant to work with

18. Carve the airfoil, keep watch on the 30% line

19. Bladecarving: Suck not Push Source: http://www.graphics.cornell.edu/academic/archartpcg/spring01/students/rr63/ROA/windworks01.jpg

20. Cut to length, cut the 120o angles, ready for the rotor hub

21. Layout holes for wood screws and studs

22. Drill the through holes for the ½” studs square to the hub

23. Sanding the hub on the lathe

24. Assemble the rotor, keep the tip-to-tip distance within ½”

25. After painting and re-assembly, tip-to-tip was 84”, 84-1/8”, 84-1/4”

26. Decided to skip the wedges

27. Wind coils Axial Flux Alternator: Stator Solder a 3-phase star Build a mold and layout coils Drill and mount Cast in polyester resin Cleanup casting

28. Keep em’ tight so they will fit into the mold

29. Clamp coils in position for soldering

30. Strip with knife, solder, shrink tubing

31. Build a mold

32. Fiberglass cloth for strength Mold release

33. Place the coils, position the three output wires in conduit, pour in polyester resin and cloth, clamp and cure

34. Free the stator and clean it up

35. Axial Flux Alternator: Rotors Buy laser-cut plates, machine the holes Position magnets with a jig Careful with those Neo magnets! Clean up and be careful Cast in polyester resin No screws needed

36. Flat, not flat My attempt at a rotor plate is on the right. Laser cut plate on the left.

37. Superglue magnets to plate to avoid movement during casting An index hole in every plate keeps things aligned

38. Build a mold

39. Do all three castings together and do it outside (strong smell)

40. Cast in Polyester resin with fiberglass clothChecking the alternating polarity

41. Stator and rotors, minimal air gap

42. Axial Flux Alternator: Magic Rectified to DC (one phase shown) An electrically charged particle moving in a magnetic field will experience a force (known as the Lorentz force) pushing it in a direction perpendicular to the magnetic field and the direction of motion: Source: http://www.wondermagnet.com/magfaq.html#q18 Most of the electric power in the world is 3 phase.  The concept was originally conceived by Nikola Tesla and was proven that 3 phase was far superior to single phase power.  3 phase power is typically 150% more efficient than single phase in the same power range.  In a single phase unit the power falls to zero three times during each cycle, in 3 phase it never drops to zero.  The power delivered to the load is the same at any instant.   Also, in 3 phase the conductors need only be 75% the size of conductors for single phase for the same power output. source: www.windstuffnow.com/ main/3_phase_basics.htm

43. Salvage steel Fabricate the Alternator Mount Prep steel, fabricate Visit a junkyard Clean, prime, paint Make strong welds Machine holes

44. Plasma torch…upping the embodied energy

45. The angle grinder cleans up ugly weldsThe type disc with flexible sanding flaps works nicely for finishing and smoothing

46. Vintage Jacobs whale tail Fabricate the Tail Cool ideas My version

47. Too much time in Kerr Scott Moved the operation home for final assembly Wife and dogs were happy Stand borrowed from Whisper 200 demo Assembly

48. Assembly: Tower adapter

49. Assembly: Alternator Bracket

50. Assembly: Hub