Building an 8foot wind turbine Brent Summerville Appalachian State University

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Building an 8-foot wind turbineBrent
SummervilleAppalachian State University
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Research In search of Plans

• Backhome Magazine article www.backhomemagazine.com
  
• www.otherpower.com
• derived from Hugh Piggotts axial flux plans or
  How to build a wind turbine
• Go with the source and follow plans closely

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Research Hugh Piggott

• Workshops in Washington, Scoraig, CAT, Edinburgh,
  Ghana, France, Costa Rica, Liverpool..

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Resources Woods Lab

• Sat in on Intro to Wood Technology
• Trained on techniques, tools, machinery and
  safety
• PracticeSanding block, cedar tool box
• Last semester for Bill Hanner

• Draw knife
• Hand plane
• Spoke shave
• Lathe
• Jointer
• Sanders
• Gluing panels
• Planer
• Bandsaw
• Drill press
• Table saw

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Resources Metals Lab

• Sat in on Intro class
• Trained on techniques, tools, and machinery
• Copper nameplate, dinner bell, apple butter stand
• Nice working with Leo and Dave

• Welding
• Mill
• Lathe
• Plasma torch
• Blacksmithing
• Grinding
• Tapping
• Sheet metal fab
• Drill press
• Iron worker

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Bladecarving

• Layout

• Basswood with termites

• Thickness, width, length

• Carve with draw knife and spoke shave

• Check, carve, sand

• Sand, sand, sand

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Jointer, planer, table saw, and belt sander to
form 1-1/2x6x52 blanks
Finished length is 48. Keep long until finished
carving. Makes for a nice blade tip.
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Start with a precise layout
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Simple tools
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Carve the taper with the drawknifeClamp and
sand to keep the blades matched
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Carve the twist and check the drop
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The drawknife can remove a lot of material
quickly, and its a good workout
Carve the thickness
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The spoke shave is pleasant to work with
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Carve the airfoil, keep watch on the 30 line
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Bladecarving Suck not Push
Source http//www.graphics.cornell.edu/academic/a
rchartpcg/spring01/students/rr63/ROA/windworks01.j
pg
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Cut to length, cut the 120o angles, ready for the
rotor hub
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Layout holes for wood screws and studs
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Drill the through holes for the ½ studs square
to the hub
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Sanding the hub on the lathe
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Assemble the rotor, keep the tip-to-tip distance
within ½
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After painting and re-assembly, tip-to-tip was
84, 84-1/8, 84-1/4
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Decided to skip the wedges
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Axial Flux Alternator Stator

• Solder a 3-phase star

• Wind coils

• Build a mold and layout coils

• Cast in polyester resin

• Drill and mount

• Cleanup casting

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Keep em tight so they will fit into the mold
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Clamp coils in position for soldering
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Strip with knife, solder, shrink tubing
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Build a mold
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Fiberglass cloth for strength
Mold release
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Place the coils, position the three output wires
in conduit, pour in polyester resin and cloth,
clamp and cure
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Free the stator and clean it up
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Axial Flux Alternator Rotors

• Buy laser-cut plates, machine the holes

• Careful with those Neo magnets!

• Position magnets with a jig

• Cast in polyester resin

• Clean up and be careful

• No screws needed

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Flat, not flat
My attempt at a rotor plate is on the right.
Laser cut plate on the left.
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Superglue magnets to plate to avoid movement
during casting
An index hole in every plate keeps things aligned
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Build a mold
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Do all three castings together and do it outside
(strong smell)
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Cast in Polyester resin with fiberglass
clothChecking the alternating polarity
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Stator and rotors, minimal air gap
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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.wondermag
net.com/magfaq.htmlq18
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
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Fabricate the Alternator Mount

• Salvage steel

• Visit a junkyard

Prep steel, fabricate

• Make strong welds

• Clean, prime, paint

• Machine holes

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Plasma torchupping the embodied energy
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The angle grinder cleans up ugly weldsThe
type disc with flexible sanding flaps works
nicely for finishing and smoothing
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Fabricate the Tail

• Cool ideas

• Vintage Jacobs whale tail

My version
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Assembly

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

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Assembly Tower adapter
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Assembly Alternator Bracket
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Assembly Hub
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Assembly Back Rotor
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Assembly Stator
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Assembly Front Rotor and J-Box
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Assembly Tail
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Assembly Ready for Blades
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Costs

• Minimum for a new 1kW turbine is about 1700
• My cost 836

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Conclusion

• Well done plans
• Slight customization
• No wedges
• Wiring details
• Nose cone
• Lots of work
• Use of magic
• Lift
• Electricity
• Economical
• To do next controller and tower

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Questions?