Building an 8-foot wind turbine
Brent Summerville
Appalachian State University
Research: In search of Plans
• 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: Hugh Piggott
Workshops in Washington,
Scoraig, CAT, Edinburgh,
Ghana, France, Costa
Rica, Liverpool…..
This is Jay from France.
He also came to a Beech
Mountain workshop.
Resources: Woods Lab
• 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
•Draw knife
•Hand plane
•Spoke shave
•Lathe
•Jointer
•Sanders
•Gluing panels
•Planer
•Bandsaw
•Drill press
•Table saw…
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…
Bladecarving
Basswood with
termites
Thickness, width, length
Layout
Carve with draw knife
and spoke shave
Sand, sand, sand
Check, carve, sand…
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.
Start with a precise layout
Simple tools
Carve the taper with
the drawknife
Clamp and sand to
keep the blades
matched
Carve the twist and check the drop
Carve the thickness
The drawknife
can remove a
lot of material
quickly, and
it’s a good
workout
The spoke shave is
pleasant to work with
Carve the airfoil,
keep watch on the
30% line
Bladecarving: Suck not Push
Source:
http://www.graphics.cornell.edu/academic/archartpcg/spring01/stude
nts/rr63/ROA/windworks01.jpg
Cut to length, cut the 120o angles,
ready for the rotor hub
Layout holes for wood screws and
studs
Drill the through
holes for the ½”
studs square to the
hub
Sanding the hub on the lathe
Assemble the rotor, keep the tip-totip distance within ½”
After painting and re-assembly, tipto-tip was 84”, 84-1/8”, 84-1/4”
Decided to skip the wedges
Axial Flux Alternator: Stator
Wind coils
Build a mold and layout
coils
Solder a 3-phase star
Cast in polyester resin
Cleanup casting
Drill and mount
Keep em’ tight so they will fit into
the mold
Clamp coils in position for soldering
Strip with knife, solder, shrink tubing
Build a mold
Fiberglass cloth for
strength
Mold release
Place the coils, position the three output wires in conduit, pour in
polyester resin and cloth, clamp and cure
Free the stator and clean it up
Axial Flux Alternator: Rotors
Buy laser-cut plates,
machine the holes
Cast in polyester resin
Careful with those Neo
magnets!
Position magnets with a jig
No screws needed
Clean up and be
careful
Flat, not flat
My attempt at a rotor plate is on the
right. Laser cut plate on the left.
An index
hole in every
plate keeps
things
aligned
Superglue magnets to
plate to avoid movement
during casting
Build a mold
Do all three castings together and
do it outside (strong smell)
Cast in Polyester resin
with fiberglass cloth
Checking the
alternating polarity
Stator and
rotors, minimal
air gap
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.ht
ml#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
Fabricate the Alternator Mount
Salvage steel
Make strong welds
Visit a junkyard
Machine holes
Prep steel, fabricate
Clean, prime, paint
Plasma torch…upping
the embodied energy
The angle
grinder cleans
up ugly welds
The type disc
with flexible
sanding flaps
works nicely for
finishing and
smoothing
Fabricate the Tail
Cool ideas
Vintage Jacobs whale tail
My version
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
Assembly: Tower adapter
Assembly: Alternator Bracket
Assembly: Hub
Assembly: Back Rotor
Assembly: Stator
Assembly: Front Rotor and J-Box
Assembly: Tail
Assembly: Ready for Blades
Costs
• Minimum for a
new 1kW turbine
is about $1700
• My cost = $836
Description
(24) Neodymium Iron Boron (NdFeB) magnets
(2) 6-lb spools of #15 AWG magnet wire
(2) 35 amp bridge rectifiers
Shipping
Basswood for blades
Chevrolet Cavalier rear wheel hub
Fiberglass cloth
Wax polish
Super glue
Bondo polyester resin
SS fasteners and spray paint
2-3/4" hole saw
Drill bit set
1/2" Plywood
3" hole saw
Plugs
White box cover
White exterior house paint
White primer
1-1/4" pipe
Paint brush
Grinder disc - resin
Grinder disc - sanding
3/8" plywood
3/4" plywood
Steel and SS threaded rod
Source
Forcefield
Forcefield
Forcefield
Forcefield
Tech Dept
T&T Auto Salvage
Walmart
Walmart
Walmart
NAPA
New River
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Lowes
Triplett & Coffey
Total
$
156.00
$
110.00
$
11.00
$
23.60
$
50.00
$
30.00
$
7.88
$
1.88
$
1.47
$
47.60
$
40.86
$
17.47
$
17.64
$
4.15
$
13.66
$
1.98
$
0.98
$
8.97
$
10.27
$
12.64
$
8.47
$
2.97
$
7.47
$
17.75
$
10.98
$
220.00
Total
$ 835.69
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
Questions?