Axial flux windmill plans

or "How to build a wind turbine"
hugh@scoraigwind.co.uk

Introduction

The term 'axial flux' refers to a type of alternator where the magnets are mounted on disks and the flux between them is parallel to the axis of the shaft.  This is unlike conventional alternators whose flux is radial across the air gap. The brakedrum alternator is a radial flux type.

Lately I have been developing construction techniques for axial flux alternators.  In 2001, I made a construction manual available for free down load from this site.  Since then I have taught a lot of courses and my ideas have moved forward.  I have made the process simpler and I have made the alternator much more powerful by using neodymium magnets.

You can see pictures of the construction process in action during my my latest workshop course in the USA by going to the picture pages for the course.  There are two slightly different versions of the design - one using inches and one using metric measurements.  Both are described in full.  There are also plans at the end of the document for a smaller alternator using a 4 foot diameter rotor (blades).

There is a lot of exciting new stuff going on at the Otherpower discussion board where Dan is extending the design and using old Volvo parts to do it based on what we did on the course in April.  Dan has made a page about his latest machine.

Other books

The February edition of the plans is just freshly printed!
(with black and white photos)

now with 3D CAD images


                   How to buy these 'axial flux windmill plans'
Prices including shipping:
        UK £10.60
Europe €  17
World US$ 21
Please send cash and not checks or money orders from overseas.  UK cheques in pounds are OK
If you send foreign currency money orders the bank will steal half of it.  If you send cash it will get here safely.
Here is my address
Hugh Piggott
Scoraig, Dundonnell
Ross shire
IV23 2RE
Scotland, UK

NOTE: I SHALL BE OUT OF THE UK TEACHING A COURSE IN THE USA FROM 8th -22nd APRIL.
I SHALL DEAL WITH ANY ORDERS THAT REACH ME AFTER 6th APRIL ON MY RETURN.
PAYPAL ORDERS REACH ME ALMOST IMMEDIATELY BUT LETTERS TAKE A FEW DAYS.

Or you can pay by credit card at paypal with the button below


 

click here for a series of snapshots of the document, or read on for full details....

Dear Hugh,
I just finished your latest book.  Damn, it's good. Great information and written very clearly.  If you are ever near Denver Colorado and want to get a beer let me know.
Sincerely.
John Steele

also now available from 

This is a pre-publication edition, produced in small batches.  A final version will be available in a few months. This document will probably supercede the brakedrum plans although they will still be of interest to some readers.  It's easier to build and involves less hunting around for parts.  The brakedrum idea has a lot going for it, but it's not the way I would do it now (ten years on).


The plans describe how to build two machines.  Both have axial flux alternators and 3-bladed wind rotors. 
 The large one has an eight foot diameter rotor and 500 watt output.
The smaller one (below) is half the diameter and  one quarter of the output.
We only use a single magnet disk on the smaller machine.


"I like the plans and the info, I really feel like I
understand everything in it....
What I really liked was the way the "Little Pancake"
machine was thrown in at the end. With just a couple
of pages we have a complete constuction plan, once we
know the principals. Reminds me of house plans, all
you need is some drawings, notes, a good material list
and someone to ask questions when you get stuck. "
Ron Dinishak

CONTENTS (52 pages including cover)
Introduction 2
Blades 2
Alternator 2
Furling system 2
Units 2
Tolerances 2
Glossary 4
Notes on workshop safety 7
GENERAL 7
SPECIFIC HAZARDS 7
METALWORK 7
WOODWORKING 7
RESINS AND GLUES 7
MAGNETS 7
ELECTRICAL 7
BLADE THEORY 8
Blade power 8
Blade speed 8
Blade number 8
Blade shape 8
Carving the blades 9
STEP ONE is to create the tapered shape. 9
STEP TWO carving the twisted windward face 9
Checking the drop 10
STEP THREE carving the thickness 10
STEP FOUR Carve the curved shape on the back of the blade 11
STEP FIVE Assembling the rotor hub. 12
Cutting the roots to 120 degrees 12
Marking and drilling the plywood disks 12
Clamping the blades together 12
Drilling holes for the mounting bolts 13
STEP SIX Cutting out and gluing on the wedges 13
ALTERNATOR THEORY 14
The stator 14
Preparing the bearing hub 15
Drilling out the 1/2' [12 mm] holes in the flange 15
Fabricating the alternator mounts 16
Drilling the magnet rotor plates 18
Making the coil winder 19
Making the stator mould 20
Mark out the shape of the stator. 20
Cut out the stator shape in plywood. 21
Wiring exit holes 21
Screw the mould to its base 21
ELECTRICAL THEORY 22
Winding the coils 22
Connecting the coils 23
Hints for soldering 23
Soldering the coil tails 23
The ring neutral 24
The output wiring 24
Casting the stator 25
Dry run 25
Putting it together 25
Removing the casting from the mould 26
The magnet-positioning jig 26
Making the two rotor moulds 28
Index hole 28
Parts of the moulds 28
Casting the rotors 29
Preparation 29
Handling the magnets 29
Dry run 29
Checking for magnet polarity 29
Putting it together 29
FURLING SYSTEM THEORY 30
Why furl? 30
How the furling tail works 30
Controlling the thrust force 31
Fabricating the tail hinge 32
The tail itself 33
Cutting out the tail vane 34
Mounting the heatsink 35
Assembling the alternator 36
Preparation 36
Hub and shaft 36
Stator mounting holes 36
Back magnet rotor 36
The stator 37
Front magnet rotor 37
Testing the alternator 38
Short circuit tests 38
AC voltage tests 38
DC voltage tests 38
Connecting the rectifier 39
Connecting the battery 39
Fuses or circuit breakers 39
Connections 39
Brake switch 39
Choosing suitable wire sizes 40
Wire type 40
Fitting and balancing the blades 41
Checking the tracking 41
Balancing the rotor 41
Fine tuning 41
Guyed tower ideas 43
Controlling the battery charge rate 44
Shunt regulator circuit 44
Using polyester resin 45
Mould preparation 45
Small machine supplement 46
Blades 46
Bearing hub 46
The shaft 47
Rotor moulding 47
Stator mould 49
Assembly of the stator 49
The yaw bearing 50
The tail bearing and tail 50
Wiring up the battery 51
Workshop tools 52
 
 

Some snapshots.

The cover changes as I bring out new editions....  the latest is February 2004,.
thisshows an older edition.