EOLIAN GEN DIY.pdf

7/27/2019 EOLIAN GEN DIY.pdf

1/187

Homebrew 10' Wind Turbine, METALWORK

Homebrew Wind Power by Dan Bartmann and Dan Fink.The best book out there about building

and flying do-it-yourself wind turbines. We know, because we wrote it!

Order it from our Online Store HERE.

This page is one of a series that were the nucleus for our newbook, Homebrew Wind Power

.

Everything here is pretty much correct, and you can build a successful,

reliable and quiet 10 foot diameter wind turbine from the free information

on these pages.

But--please note that as of January 1, 2009 we are no longer updatingthese free plans here!We have made numerous postings on our Discussion Board about things we

do differently from this wind turbine design now, and our book Homebrew

Wind Power goes into much more detail about all aspects of building wind

turbines from scratch, including revisions to this page. The new blog for

our book, HomebrewWind.com, is where you'll find our latest updates,

thoughts, corrections of errors in the book, rants, raves, CAD drawings,

videos, and random bits about building wind turbines.

1


2/187

Metal Work Part 1: On this page we build the main chassis for the machine.

Metal Work Part 2: On this page we fabricate the tail boom.

Coil Winder: This page details construction of the coil winder.

Stator mold: Details of the mold in which we cast the stator.

Stator: Detail of winding the coils and casting the stator.

Magnet Rotors: Building the magnet rotors.

Alternator Assembly: Assembling the alternator

Wind turbine blades: How to carve the blades

Blade assembly: How to assemble the blades

Rectifier: How to build the 3 phase rectifier

Towers: An older page with thoughts about towers and some ideas

This chapter will describe how we build the 'frame' for the wind turbine.

This involves a fair bit of metal work. To do this you'll need to have

the ability to cut/grind and weld steel. If you're new to this type of

2


3/187

work it might pay to practice your skills on some scraps. The tolerances

with this are not terribly, again - the design is very forgiving. But some

of the welds are critical so you need to be a bit careful. Also keep in

mind the dangers of metal work. This is the most dangerous work you'll

do to build the wind turbine. Metal is often sharp when you cut it. Grinding

can be fairly dangerous - lots of shards flying around and I've seen grind

stones explode before, so be sure to wear a face shield. Cutting with a

torch or welding has it's obvious hazards (molten hot steel and sparks

flying). Just follow proper safety proceedures and odds are you'll live

through it.

Materials List

1/4" thick steel plate, 15" square (stator bracket, tail bracket, diskto support the back of the spindle)

1" sched 40 pipe, 6' long (tail boom, tail pivot)

1.25" sched 40 pipe, 9" long (tail bearing)

2" sched 40 pipe, 4" long (to attach alternator to yaw bearing)

2.5" sched 40 pipe, 12" long (yaw bearing) 3" sched 40 pipe, 3.625" long

(pipe to support wheel spindle and stator bracket) 1.25" x 1/4" bar stock,5' 6" long (tail boom gusset, tail vane bracket)

3


4/187

Pictured above are all the parts you'll need to make (or have made) before

you start. Not pictured above are the parts of the tail itself which we

can discuss later, because it is a seperate part.

1 - Stator bracket. The stator bracket is cut from 1/4" thick steel plate.

It serves to support the front of the wheel spindle (on which the main

wheel hub/bearings go) and it supports the stator. To lay it out, find

center and draw two circles. The inner circle is 4" diameter, the outer

circle is 15" diameter. Lay out 3 'spokes' 120 deg apart. The spokes are

1.5" wide at the outer diameter and 2" wide where they meet the inner 4"

dia circle. Centered on each spoke at 13.75" diameter is a 1/2" hole (these

accept the studs that will mount the stator). In the center of the bracket

is a 1.25" diameter hole. This fits the wheel spindle. You can cut this

out with a torch, or a plasma cutter easily. If those tools are not

available, you can simplify the design keeping in mind that the criticalmeasurements are the locations of the 1/2" and 1.25" holes. Some folks

will make the inside 4" dia circle with a hole saw and then make the spokes

with bar stock. While it doesn't look quite as neat, it works just as well.

The spokes should be fairly rigid so if you do use bar stock use at least

1.5" x 1/4", any thinner might bend under the torque that the stator will

impose upon it.

2 - Yaw bearing cap. The yaw bearing cap is simply a disk of 1/4" steel

with a 3/4" dia hole drilled in its center. It will be welded to the top

of the yaw bearing and the hole will accept the cord from the alternator

which will run down the center of the tower. When making the magnet rotors

you cut a 2.75" diameter hole in their center. Use the scrap from one of

the magnet rotors for this - it's the perfect diameter, all you need to

do is drill the hole in the center.

3 - Spindle, part #BT-88. This is the spindle that our wheel hub (Dexter

part #81-9A) fits. It's probably the most common spindle in use for 1000

pound trailer axels and it's widely available. There are other slightly

cheaper spindle/hub setups but I prefer this one. It's the best choicebecause it's widely availabe and it's machined on both sides which makes

life much easier for us. You can certainly modify the design to accept

other brands of spindle/hub assemblies but I think it's easier to stick

with the Dexter parts here. Check out the appendix for suppliers.

4 - This is the 3" dia sched 40 pipe that supports all the parts of the

alternator. It's 3.625" long and we cut a 2.5" hole in it with a hole saw.

4


5/187

The hole can be cut on center, but I prefer to cut it slightly off center.

Cutting it towards one side allows us to push the whole alternator foward

in relation to the yaw bearing slightly and gives us a bit more clearance

between the stator bracket and the yaw bearing. It also gives us slightly

more clearance between the blades and the tower. Use a good high quality

bi-metal hole saw. Be sure to run the drill press at it's lowest possible

speed and use plenty of cutting oil.

5 - Rear spindle support. This disk is just under 3" in diameter (cut it

out with a torch, or a 3" hole saw) and it has a 1.25" diameter hole in

the center which fits around the back of the wheel spindle. The stator

bracket supports the spindle in the front, this disk supports it in the

rear.

6 - Connects alternator to yaw bearing. This is cut from 2" diameter pipe.One end is coped with a hole saw so that it can be welded to the yaw bearing,

the other end is left flat, and fits into the 3" pipe which has a 2.5"

hole cut to accept it (part #4).

5


6/187

When we cope this part with a hole saw the distance from the center of

the hole saw to the other end of the part should be 3.25". We usually use

a 2.5" diameter hole saw to cope this, and then we need to touch it up

a bit with a grinder so that it fits nicely against the yaw bearing.

7 - Yaw Bearing. This is the part that slips over the tower top. It's 12"

long, made from 2.5" sched. 40 pipe. This is the part that will fit over

the tower top.

8 - Tail bracket. This will sit between the yaw bearing and the tail pivot

(the pipe that the tail will hang, and pivit on when the machine furls).

It's also cut from 1/4" steel plate. It's 3.5" tall, 1" wide at the bottom

and 2.125" wide at the top.

9 - Tail pivot. This gets attached to the tail bracket and the tail will

slip over it and 'hang' on this part. In high winds, the tail will pivot

on this pipe.

Once all the pieces are cut out you begin welding the machine together.

The first step is to build the part that supports the alternator. Once

that's finished you attach the tail bracket to the tail pivot, and then

you weld both those parts to the yaw bearing.

6


7/187

Start by gathering the [parts pictured, the wheel spindle, the stator

bracket, the 3" dia pipe with the hole in its side and the 3" disk with

the 1.25" hole in its center.

I like to use an old 3 jaw lathe chuck for this, but if that's unavailable

a decent sized vice should work fine. You need to clamp the wheel spindleso that the machined part is facing down, and put the stator bracket around

7


8/187

it as shown in the picture. 6.625" of the wheel spindle should be sticking

up from the surface of the stator bracket. The stator bracket may not be

perfectly flat but get things as close to square as possible (so that the

angle between the stator bracket and the spindle is always 90 degrees).

Tack weld the spindle to the stator bracket in 3 or 4 small spots on

different sides. This will hold it in position nicely so that you can

really weld it there. If you don't tack weld it first and just start welding

around the circle it will be pulled out of square as your welding because

weld's shrink as they cool.

After you've tack welded the spindle to the stator bracket go ahead and

weld it there.

8


9/187

Now center the 3" pipe on the stator bracket. The height of the spindle

should be the same as that of the pipe. The 3" pipe has the 2.5" diameter

hole you cut in one side. If you cut the hole off center (more towards

one side then the other) then put the pipe on the stator bracket so that

the hole is most distant from the stator bracket. If you cut the hole on

center it obviously doesn't matter. Where the 2.5" diameter hole points

with regard to the spokes on the stator bracket is not terribly important,

but we usually like to put it opposite one of the spokes. This way when

the wind turbine is together, we'll have 1 of the spokes coming out from

the stator bracket pointing exactly away from the yaw bearing... it just

looks a bit neater I think and it makes the machine less fragile if we

have to ship it somewhere, but it doesn't affect the workability of the

wind turbine. Don't weld the 3" pipe to the stator bracket yet...

9


10/187

Now take the 3" diameter disk with the 1.25" hole in it, and position it

inside the 3" pipe. It should fit around the back of the wheel spindle

and inside the 3" pipe as shown in the picture. A magnet serves nicely

to hold it there before you tack weld it.

10


11/187

Once everything looks good and centered go ahead and tack weld everything

together. (3" pipe tack welded to stator bracket, 3" disk tack welded to

3" pipe and wheel spindle)

Then weld it all together for good as shown in the picture.

11


12/187

It's not necessary but it'll look much nicer if you take the time to grind

your welds down and smooth things out. Now is the time for this, once we

weld this part to the yaw bearing you'll not be able to get at some of

the welds very well with a grinder.

Now we'll weld the assembly that we just finised to the yaw bearing. There

are a couple of weird angles involved here and the distance between the

yaw bearing and the wheel spindle is fairly critical. We've built a jig

to make assembly of a wind turbine quite easy and if you plan on building

more than one machine such a jig may pay off. But it's fairly easy to do

without one. Start by putting the spindle/stator bracket assembly that

you just finished on top of a 1/2" thick shim (a piece of wood or 1/2"

thick steel or whatever...).

12


13/187

The yaw bearing is 12" long. Mark the center of it at 6".

Pictured above is the layout and were looking at it from the bottom of

the wind turbine. You can see how the 1/2" shim under the spindle/stator

bracket assembly pushes the alternator foward a bit. If you can imagine

a vertical line through the center of the yaw bearing (the 12" x 2.5" pipe)parallel to the spindle, there should be 5" between it and the center of

13


14/187

the spindle. In other words... when we're finished the center of the

alternator will be 5" to one side from the center of the tower.

Looking at the same thing from the side. We've put a 3/4" shim under the

top of the yaw bearing. When finished, this will cause the alternator to

be tipped back about 5 degress so that the wind turbine blades are tipped

back and have nice safe clearance between their tips and the tower.

14


15/187

Tack weld this all together. Inspect it to make sure the offset between

the spindle and the yaw bearing is correct, and that all the angles are

correct. If all looks good then weld it together.

Get the tail pivot bracket and the tail pivot (parts 8 and 9 as shown in

the previous picture). Mark the center of the tail pivot (4.5") and

position the bracket so that it's top (the 2.125" wide part) is at the

half way mark on the tail pivot. Tack weld it at the top and bottom and

then quickly on each side as shown in the picture above.

15


16/187

Looking down at it from the top it should look like the picture. If

everything looks right, then weld it. This needs to be a good weld with

good penetration because the tail hangs on this part.

Take the main part of the wind turbine and put it in a vice so that it's

tipped at 45 degrees as shown in the picture.

16


17/187

Put the tail bracket and pivot on top so that it's pointing straight up,

and tack weld it there. Again, inspect it - make sure everything is

straight and square and if it's all good then weld it there. This is

probably the most critical weld on the machine. The tail can slam around

on the tail pivot in high winds and all this weld takes all the abuse.

This needs to be a high quality weld with good penetration or you risk

having the tail fall off which can be disastrous especially if it hits

the blades. We've never had this happen but I always worry about it. If

you weld this well there should be no problem.

17


18/187

Now you can weld the yaw bearing cap to the top of the yaw bearing as shown

in the picture.

Pictured above is how your machine should look from the top.

18


19/187

Shown in the picture above is the same machine veiwed from the side. All

thats left is to build the tail.

The main chassis for the wind turbine is finished, so at this point the

tail boom needs to be fabricated. The tail bearing hangs/pivots on the

the tail pivot which is welded to the frame of the wind turbine. The pivotwas attached to the yaw bearing via an angled bracket. The bearing is made

19


20/187

from 1.25" sched 40 pipe. It's the same length as the pivot (9"). It needs

to be notched so that it can fit over the 1" pipe we used for the pivot,

and the notch will fit over the bracket that attaches the pivot to the

yaw bearing. One side of the notch will serve as a stop to hold the tail

in its proper position. Pictured above we're preparing to notch the tail

bearing with a cutting torch. Two of the 1" x 2" magnets stuck to the

back of a piece of angle iron makes for a nice jig/template to help do

a neat job. Again, the tail bearing is made from 1.25" sched. 40 pipe,

it's 9" long. Cut the notch half way up the pipe (so 4.5" is notched,

and 4.5" is left undisturbed).

Pictured above George is cutting one side of the notch using the angle

iron to help guide the torch. Once that sides cut we turn it about 160

deg and cut the other side of the notch. We say to notch out about 160

deg. This is the maximum width that you should make the notch, in mostcases you could make it narrower (120 - 140 deg is usually fine) - so this

is not critical. If the notch is too narrow then the tail may not be able

to fully furl. This depends on the width of the notch and also the thickness

of the welds which attach the tail pivot to the tail bracket. Once both

sides of the notch are cut, you can cut between the lines and finish the

notch. Save the scrap, you'll need it later.

20


21/187

Shown in the picture is how the tail bearing should look after it's notched

looking up at it from the bottom. There are are plenty of other ways to

do this. If a cutting torch is n ot available, this notch is easy to

make with a jig saw, hack saw - band saw etc... there are lots of different

ways to do things. A milling machine does nicely too, but it leaves kind

of a small scrap (the piece that comes out of the notch) and we do need

the scrap. I prefer to have the scrap larger and save time so a bandsaw

or torch is preferable.

21


22/187

Shown above is the notched tail bearing and the scrap you cut out. Use

a hammer and beat the scrap a bit flatter so that it's inner diameter fits

nicely around the outer diameter of the tail bearing.

Put the tail bearing on the machine and tack weld a 1" diameter plug (it

could be up to 1.25" diameter) in the top of the tail bearing. It needs

22


23/187

to fit down inside the tail bearing so that the top of the plug is flush

with the top of the pipe.

Turn the tail bearing all the way counter clockwise so that it comes to

stop against the notch on the side opposite that shown in the picture.

(one side of the notch needs to come up against the tail bracket, this

is the tails 'normal/unfurled' position)

23


24/187

Tack weld the scrap from cutting the tail bearing notch on the other side

(the side opposite the alternator) of the tail bearing as shown

above. This serves as a reinforcement should the tail come slamming down

from the furled position back into the normal position. It'll help keep

the notched tail bearing from getting bent or cracking around the notch.

The tail boom is fabricated from 1" shed. 40 pipe, it's 5' long. You need

to cope one end of it so that it fits against the tail bearing. The angle

between the tail bearing and the tail boom should be about 20 degrees.

Pictured above we're cutting a 20 deg angle through half the pipe (leaving

the other half cut at 90 deg) - kind of a quick/cheap way to cope the pipe

so it fits the tail bearing.

24


25/187

Thats the finished cut on the tail boom. This will fit nicely against

the tail bearing for welding.

Thats how it should look from the side. There's about a 110 deg angle

between the tail pivot and the tail boom. Its a common mistake for folks

to weld the tail boom at 90 deg to the tail pivot. The end result will

25


26/187

be a tail that points down and looks funny (itll work that way but it looks

funny). I prefer to have the tail pointing upwards a couple degrees.

26


27/187

That's how it should be from the top. When the tail is in it's position

of rest (the normal running position, turned all the way

counterclockwise as far as it will go) it should be about 10 deg to the

left from parallel with the wind (parallel with the spindle). Get someone

to hold the tail so that it's in the right position as shown in the two

pictures above and tack weld it there. Weld it so that you can look at

it - and still bend things around a bit if necessary. The reason the tail

is sticking out at an angle about 10 deg out of parallel with the wind

direction is to compensate for the fact that the alternator sticks out

5" on the opposite side. When the wind is pushing against the

blades/alternator there is a force trying to turn the whole machine

counter clockwise (assuming you're looking down at the machine). The tail

is angle slightly to the other side to help counteract this force. That

said, it's important to keep in mind that wind turbine blades when running

at speed *want* to run square with the wind. In our experience the 10 degangle in the tail is not critical, anything between 5 - 15 degrees should

work fine. Like most things with this design, it's not worth fretting a

great deal over getting things perfect. If you're a couple degrees off

it won't matter.

Then finish all the welds.

27


28/187

Make a gusset 30" long from 1.25" x .25" bar stock. Cut it to length (30")

then lay it under the tail so you can mark where it needs to be cut with

a soap stone. Then we cut it with a torch or a bandsaw so it fits

well. This gusset probably isn't needed if the tail is welded to the tail

bearing well - but it looks nice and adds some insurance. The 30" length

is not critical.

28


29/187

Weld the gusset onto the tail boom.

This is the 'stop' (or bumper) that you need to fabricate, and weld to

the tail boom. This will bump against the yaw bearing when the machine

is fully furled and make sure you have about a 10 deg angle between the

blades and the tail (as shown in the drawing above) and insure that the

tail can never hit the blades. The piece shown above is fabricated from

1/4" flat steel. The only critical measurment is the one that stands

between the tail boom and the yaw bearing (should be 2" if all the angles

are perfect in your machine but slight variations could change this). The

one pictured is 2" wide at the bottom, 2" tall, and 1.5" across the top.

It's angled on one side only for the sake of appearance.

29


30/187

In the picture, George is clamping the bumper in there between the tail

boom and the yaw bearing. It's helpful to have someone do this so you can

position the part in its proper place (double check that its long enough

to keep the tail out of the blades). It should be square with the yaw

bearing and fairly well centered on it (the 1.5" long surface touches the

yaw bearing on center when the machine is furled). When those two

conditions are true - weld it on there.

30


31/187

Theres a picture of it welded on, the tail is sitting in its normal running

(unfurled) position.

The image above shows the machine in it's furled position. You can see

how the stop comes up against the yaw bearing. Notice the angle between

the tail boom and the stator bracket - this same angle will exist between

the tail boom and the blades. Setup this way the tail can never come into

the blades.

31


32/187

The last metal part to fabricate is the tail vane bracket. Its 34" long

made from 1.25" x .25" bar stock, and each end has a 3/8" hole drilled

1" from the end (to hold the wooden tail vane which we've not made

yet). Use a square as shown in the picture. Clamp the tail vane bracket

square with the tail boom and 9" from the end of the tail boom. Again -

none of these measurments are critical, it's just our standard way of doing

things. Tail shape is not critical so if you decide to make a different

shaped tail for the machine then it will probably make sense to change

the dimensions here.

32


33/187

Use a small torpedo level to make sure the bracket is vertical. Once

everything seems right tack weld it on there and inspect everything. Since

it's tack welded you can still make changes if needed. Once it looks good,

weld it permenantly.

Now all the metal work is done save a bit of grinding perhaps to cleanup the welds.

33


34/187

Coil Winder Instructions.

Before we can build our wind turbine there are a few tools we need to make.

We'll need to make moulds for the magnet rotors and the stator, and we

need to make a coil winder. It's simply a spool made from wood, with a

crank that we can wind our coils on. The next couple of pages will detail

exactly how we made ours, but the idea here is simple and there are surely

many simpler ways to do this. Some of the thoughts that went into this

design included: having a fairly large crank which makes handling thicker

wire easier, and having the back disk oversized, with steel pins so that

we can change the form of the coil and build different/larger sizes of

coils if necessary. Ours is also constructed like this because these were

all materials we had on hand. Your situation may be different. For a one

off project, this could all be simplified some. Before building this itmight be helpful to read the section on building the stator so you

understand how we use this tool - that will help you to understand why

we make it this way, and give you ideas about other possible ways to make

a good coil winder. Listed below are all the parts we'll require for this

project.

Parts List- " Plywood disk 6" diameter

-" Plywood disk 4" diameter

-3/8" plywood rectangle, " x 1.5"

-5/8" plywood disk 6" diameter

-1" wooden dowel 2.5" long

-1.5" steel square tubing 7" long

-1" x " steel barstock 5" long, qty 2

-5/16 - 18 bolt, 3.5" long

-5/16 - 18 bolt, 2.5" long

-" SAE washer, qty 2

-5/16 - 18 wing nut

34


35/187

-16 Penny nail, qty 5

First step is to cut out some metal parts. I find the portable metal cutting

band saw fast and easy, but a hack saw, sawzall or even a torch would work

fine. In building wind turbines we often have to adapt a design to

accommodate the tools are resources that are available to us, sometimes

this requires some imagination.

35


36/187

Whenever we cut metal there are sharp burrs at the cut. It's nice to clean

up all our cuts (and welds) with a grinder. Pictured above George is

grinding the cuts (he should be wearing a face mask).

Here is the square tubing we cut that supports the coil winder. We need

to cut it off square at 7" length, and drill a 5/16" hole through it.

36


37/187

Cut two of these 5" long from 1" x " tubing. One will be welded to the

bottom of the tubing. The other requires a hole to be drilled and tapped

5/16" - 18. This one will serve as the crank, and the handle will screw

into the tapped hole.

Make this part from a 1" diameter wooden dowel. Overall it's 2.5" long,

and we drill through 21/64" so that it turns freely on the 5/16" bolt.

We also need to drill in 5/8" with a 5/8" drill bit to accommodate the

head of the bolt.

37


38/187

We cut the dowel off with any saw, and then drill it out on the lathe.

While it's on the lathe it's nice to round the edges and sand it a bit.

If you don't have a lathe, you could do this carefully with a hand drill

or drill press, or - if it's just for one machine the wooden handle is

not very important, it just makes for more comfortable winding.

Drill a hole (9/64") through the 3.5" long bolt. The hole should be drilled

on center at 2 3/8" from the bottom of the bolts head. The 9/64" hole is

a good diameter to fit a 16D nail pretty tightly.

38


39/187

The nail serves as a pin to lock the spool to the shaft (the bolt is the

shaft)

39


40/187

Make 3 wooden disks. One is of 5/8" plywood (I prefer Baltic birch for

this) and is 6" diameter. Another is also 6" diameter, from " plywood.

We also need a smaller 4" diameter disk (in some of the pictures we show

a larger diameter disk on the front of this coil winder that's been cut

on two sides down to only 4" tall with two slots. To avoid confusion just

make that disk 4" in diameter and keep the slot on one side as described

later in the plans). All of these need a 5/16" hole in the center. The

6" dia 5/8" thick disk needs a slot cut to accommodate the nail we use

for a pin. The slot should be about 1.4" wide and deep, and 3.5" long sothat a 16 penny nail with its head cut off fits in there. Both the 6" dia

5/8" thick disk, and the smaller 4" disk need 4 9/64" holes drilled as

shown in the picture above. These holes will accommodate pins around which

we'll wind the coils. Take the 6" diameter " thick disk, and drill 4 holes,

3/32" evenly spaced on a 5" diameter, and run a countersink in them. We'll

be using wood screws to attach this disk to the thicker one, and we want

the heads flush with the plywood. It's important that holes line up nicely

here. I would suggest screwing the smaller disk, and the thicker 5/8" disk

together and drilling all the holes together.

40


41/187

Cut a piece of 3/8" plywood rectangular as shown above. It's 1.5" tall,

and " wide. Drill a 5/16" hole through the center. This serves as a spacer

between the disks.

Weld the 5" long bar stock that has no holes in it to the bottom (the end

furthest from the hole) of the square tubing. This serves as a base sothat we can clamp the coil winder to a workbench.

41


42/187

Put the shorter bolt (2.5" long) through the wooden handle and thread it

into the 5" long bar stock which has been drilled and tapped to accept

the bolt. Put a washer in between the handle and the bar stock. Thread

the bolt in so that the threads come flush with the back of the bar stock,

and the handle should turn freely.

42


43/187

Turn it over and spot weld where the bolt is through the bar stock -this

assures that the handle will never come loose.

Take the longer bolt (the one with the hole drilled in it) and weld it

to the other end of the handle as shown in the picture. It needs to be

square!

43


44/187

Put a washer over the bolt that's sticking out (we always want a washer

between any part that turns, and any part that doesn't) and insert the

bolt through the hole in the square tubing.

Put another washer on and then put the 6" diameter " thick disk on. The

countersunk holes need to be pointing back, towards the handle.

44


45/187

Insert the pin through the shaft and center it.

Put the 5/8" thick disk on the shaft so that it fits over the pin that's

through the shaft, and bring it tightly against the " thick disk.

45


46/187

Use 5/8" long wood screws to screw the two disks together coming in through

the back of the coil winder, through the 4 holes we drilled and countersunk

earlier. The screw heads need to be flush, they must not stick out.

Put the small rectangular spacer on and align it so that its in between

all the 4 holes which will hold the pins around which the coil is formed.

Tack it there with a touch of glue so it doesn't rotate.

46


47/187

Cut a slot in the front 4" diameter disk as shown. It should be about 1/8"

wide and should come right to the center, and stop between the two pins

that are nearest each other. We'll start winding the coils from this slot

and it needs to be centered at the narrowest part of the coil.

Cut 4 16 penny nails and cut them 1.125" long (including the head). De-burr

the ends you've cut (so they're not sharp). Once the coil winder is

finished, we'll insert these through the 4 holes in the front (4" diameter)

disk and they'll also go into the holes in the rear disk, so that the disks

are pinned together and the pins will be supported both in the front and

in the back. These 4 pins will form the center of the coil.

47


48/187

Put the front on and use the wing nut to hold it on there. (Ours which

is featured in the pictures uses a normal nut - a wing nut is easier though)

The coil winder is finished, we'll discuss how to use it when we start

making the stator.

The stator consists of 9 coils equally spaced around a circle, wired in3 phase star configuration. Once you finish winding and connecting our

48


49/187

coils you'll need to cast them in resin to form the stator. The stator

is a disk 15.5" diameter with a hole in the middle 5.75" in diameter. To

make this we need to build a mold out of plywood. This chapter will show

exactly how we built ours. Of course many things could be changed and it

would still work fine (or maybe even better). We call for all 1/2" thick

birch plywood (birch plywood is stronger and smoother) for all the parts.

You could use thicker stuff for the lid and the base, but the middle must

be 1/2" thick - the stator has to be 1/2" thick when we're finished.

Materials- 18" square birch plywood 1/2" thick, qty 2

- 16" diameter birch plywood disk, 1/2" thick

- 5.75" birch plywood disk, 1/2" thick

- 1/2" - 13 tpi threaded rod 2.5" long

- 1/2 - 13 tpi nut

- 1/2" washer

- 13 3/4" long wood screws

49


50/187

Start by cutting out an 18" square piece of plywood. This will be the bottom

of the mold

Find the center of the square. (an easy way is to draw light lines from

corner to corner - where they intersect is center). Use a compass to draw

3 circles on the bottom of the mold. One should be 8" diameter, one 12"

diameter, and one 15.5" diameter. The space between the 8" dia and the

12" dia circles is the area that the magnets will rotate over and the coils

will need to be centered over these lines. The 15.5 diameter circle shows

the outside diameter of the stator and this will help to make sure the

middle section of the mold is centered perfectly.

50


51/187

There will be 9 coils and it's nice to draw lines in the mold so that we

know the maximum permissable size of each coil. It will also help to be

sure that the coils are spaced around the circle properly. In order to

divide the circle into 9 equal spaces you need to know the length of one

side of the circle. We worked from the 12" diameter circle we drew. An

easy way is to use the table of Sides, Angles and Sines. Multiply the sine

of the angle (20 deg for 9 sides) times the diameter of the circle you

wish to divide (12"). The sine of 20 deg (.342) * 12 = 4.104" per side.

51


52/187

The table of sides, angles and sines for the most common numbers we use

in these alternators. The angle given is half the actual angle of any

segment. To use the table, pick the number of segments (sides) you need

to divide the circle into. Multiply the Sine by the diameter of the circle.

Set the compass to that length. Pick a starting point and make marks with

the compass about half way around the circle. Then go back to the starting

point and work in teh opposite direction. This will lessen any error that

might come up from imperfect measuring or rounding of numbers, but

hopefully you'll come out very close!

52


53/187

Use dial calipers to adjust your compass as shown in the picture. Then

pick a starting point on the 12" circle and use the compass to divide the

circle into 9 equal parts. This is a nice way to divide any circle - it's

very handy for placing magnets and coils accurately in different sized

wind turbines.

53


54/187

Draw lines from the center to the 15.5" diameter circle to show the space

that each coil should occupy.

Make another plywood square just like the last one (18" square) and cutout

a hole in the center 15.5" in diameter. This is the middle of the mold.

Sand the cuts on the inside smooth and try to give it a very slight taper

(so that the top is just slightly larger diameter than the bottom). This

will make removing the casting easy. Drill holes ( 3/16" diameter for wood

screws) around the circle (keep them about 1/2" away from the inside edge).

If your's is like the one in the picture, you'll need at at least 9 screws

to hold this piece down flat against the bottom of the mold. Run a

countersink into the holes deep enough to be sure that all the screws will

be flush with (or below) the surface of the mold.

54


55/187

Cut out another disk 5.75" in diameter. This will be the island in the

center of the mold. It also needs to be sanded smooth and slightly tapered.

Drill 4 holes for wood screws as shown in the picture and run the

countersink in just like you did for the middle part of the mold.

Cut out another disk from birch plywood, 16" diameter. This is the lidfor the mold. Sand the edges smooth. Drill a 3/4" diameter hole in the

55


56/187

center and give it a slight taper with a round file. (sand paper wrapped

around a wooden dowel or bolt works nicely too)

Center the pieces of the mold up and screw them together with 3/4" long

wood screws.

56


57/187

If the screws come all the way through the mold, grid the sharp tips off

so nobody gets hurt by them.

Drill a 7/16" diameter hole all the way through the center of the mold.

We'll be tapping this hole for the threaded rod - since it's wood you could

use a smaller drill bit, the tap will cut wood easily.

57


58/187

Tap the hole 1/2" - 13 tpi.

Put a bit of epoxy on the threads of the threaded rod. You may need to

double nut the end of the threaded rod but usually you can screw it in

by hand. Screw the threaded rod into the hole so that the bottom of the

rod comes flush with the bottom of the mold. If any epoxy comes up to the

top of the mold wipe it off with a rag.

58


59/187

Wipe the mold down with boiled linseed oil. This will help fill the pours

in the wood. When we grease the mold before casting, this assures that

the grease will not soak into the mold and the castings will come out more

easily. It also protects the mold from water.

Once the linseed oil is dry run a bead of caulk around the edges of the

inside of the mold. This will help create a 'tapered' mold, it will also

plug any cracks between pieces of plywood to help assure the castings come

out easily.

59


60/187

Put the lid on the mold, and hold it there with a 1/2" washer and a nut

(the nut will be used to help clamp the lid down when were casting). Put

it aside untill you get around to building the stator!

Po polsku -- tumaczenie Leszek Markiewicz

How to make the Stator

The stator is the very important electrical part of the wind turbine. It

contains all the coils of wire which will have voltage induced in them

as the magnets pass over them. It's defined as the 'stator' because it

is the 'stationary' (it doesn't turn) part of the alternator. For this

project you're building a 3 phase alternator and the stator will have 9

coils. Each phase will consist of 3 coils in series and you'll make a star

connection between the phases. You'll build this in our stator mold and

the lines on the bottom of the stator mold will help to know the the coils

are the correct size, and that they're placed correctly.

Materials- 6 pounds magnet wire. (best is to use double insulated 200 deg C stuff)

- 15" diameter disk of fiberglass fabric, qty 2

60
http://www.otherpower.com/statorpl.htmlhttp://www.otherpower.com/statorpl.htmlhttp://www.otherpower.com/statorpl.htmlhttp://www.otherpower.com/statorpl.htmlhttp://www.otherpower.com/statorpl.html


61/187

- Thin viscosity Cyanocrylate glue (super glue) with accelerator.

- 1/2 Gallon polyester resin

- solder

- electrical tape

- heat shrink (optional)

- 3 brass 1/4 - 20tpi screws 1.25" long

- 12 brass or copper 1/4" washers

- 6 brass 1/4 - 20 tpi nuts

Winding the Coils

Pictured above Scott's winding with two strands of wire. This is necessary

for 12 Volt machines.

The magnet wire you need depends on the voltage of your system. Roughly

speaking, every time we go up 3 sizes in magnet wire then the wire has

half the cross sectional area. The voltage of the machine is directly

related to the number of turns in the coils. If we double the number of

61


62/187

turns, then we double the voltage. No matter what the voltage of the

machine, the coil size and weight needs to remain about the same. 12 Volt

machines require very thick wire, so thick that it makes sense to wind

with two strands in hand. (so for 12V machines we need two spools of wire

and we're handling two strands as if they were one)

- For 12 Volt machines you need to wind with two strands of #14 gage wire

in hand and each coil should have 36 turns.

- For 24 Volt machines wind with 1 strand of #14 gage wire and each coil

should have 70 turns.

- For 48 Volt machines wind with 1 strand of #17 gage wire and each coil

should have 140 turns.

If you follow the guidelines above, and the coil winder is made according

to the plan then the coils should fit nicely in their alloted space, and

the whole stator should require about 6 pounds of wire. If the rest of

the alternator is assembled properly then the machine should start

charging batteries at about 140 rpm which is nice for a 10' diameter blade.

Start by creating some kind of fixture to hold the spool of magnet wire.

I usually use a vice with a piece of threaded rod, or a wooden dowel

sticking up to put the spool. Clamp it to the work bench securely.

62


63/187

Clamp the coil winder to the workbench with a C clamp as shown in the

picture.

You'll need a pair of side cutters (to cut the wire), a pair of needle

nosed pliers (to bend the wire) and some electrical tape. If the coil

winder has a wing nut holding it together then you can use your fingersto take it apart. Otherwise you'll need a 1/2 wrench. When you bolt the

63


64/187

front on the coil winder finger tight is fine, but after all the wire is

wound on the spool the nut will be tight so - if you dont have a wing nut,

you'll need a wrench to get it apart.

About 10" from the end of the wire bend it sharply 90 deg with the needle

nosed pliers.

64


65/187

Drop the wire in the slot of the coil winder and bend the end around the

nut. (A wing nut helps here too..) This will hold the wire from slipping

when you wind the coil.

Hold the wire tightly in one hand (keep tension on it) while turning the

crank with the other hand. Be careful to keep constant tension on the wire

and try to turn the coil winder at a constant speed. I notice lots of folks

tend to turn it faster on the down stroke and slower on the upstroke -

this will usually result in a lop-sided coil (one side of the coil wider

than the other). It's important to keep constant speed and consistant

tension. Try to wind the wire in neatly but don't obsess over perfection.

I've seen some folks take over an hour to wind a coil trying to pile the

wire in perfectly. It should take no more than a minute or two to wind

a coil.

65


66/187

Once you've got the correct number of turns, pull the lead out of the slot

and twist the two ends together (1/2 twist - just enough to hold them

together). Don't twist more than you need because later you'll undo this

and it's nice not to bend up the wire more than necessary. Grab the wire

between the spool and the coil with one hand, and clip it so that there's

about 10" of wire out of the coil. (both leads coming from the coil should

be about 10" long) Take the loose end that's coming from the spool, put

it on the workbench and set something on it (the side cutters are handy

since they're probably still in your hand) so that the wire on the spool

doesn't unravel.

66


67/187

Take the end of the coil winder. The coil will come with it.

The coil should pretty much fall off the end if you just turn it over.

Do it carefully so the coil doesn't fall apart.

67


68/187

We refer the longest sides of the coil as the 'legs'. Tape the legs of

the coils with a couple wraps of electrical tape to hold things together.

One coil is finished.

Check your coils, they should fit in the stator mold as shown in the picture.

It's OK if they're a bit smaller we used #16 gage wire in the coil pictured.If you use #17 wire as called for, they'll be a bit smaller. Remember the

68


69/187

stator mold has 9 radial lines that tell us the maximum width of the coil,

and it has two circles (8" and 12" diameter) that show us the path of the

magnets. When checking the size of the coil center the hole in the coils

center over the 8" and 12" circles. In that position the coil must fit

in between two of the radial lines.

If the first coil fits well, then wind 8 more like it. In the picture we've

put all 9 finished coils in the mold, you can see how they're almost a

perfect fit. Again - you might have them come out slightly smaller than

those pictured which is fine.

Wiring the stator

69


70/187

The drawing shows how we'll wire the coils together. Each phase is numbered

and consists of 3 coils in series. We define each coil (and each phase)

to have a 'start' and an 'end'. The 'start' is the lead that comes from

the inside of a coil, and the 'end' is the from the outside of a coil.

The only thing not shown in the drawing is the 'star' connection. (In the

drawing the starts are labelled A, B, and C, the ends are labelled X,Y,

and Z) To make the star connection you'll connect the 3 starts (A, B, and

C). The only difference between the drawing and what you're going to do

is that you'll make all the connections on the inside diameter of the

stator.

70


71/187

Take 3 coils and put them in the mold in their proper position. Pick 3

spaces which are 120 deg apart. If you coud superimpose and image of our

magnet rotors over these three coils you'd see that they are seeing an

'identical' magnetic situation, therefor they are 'in phase' with one

another. (when one of them is at maximum voltage so will the other two

be). Be sure all 3 coils are same side up (the start of the coil is the

wire that crosses over the inside, and it should be facing up - you need

to be sure that no coils are 'upside down'. We are about to wire up 1 phase

of the alternator.

Take the 'end' of one coil, and wrap it around so that it points towards

the outside of the mold - and tape it to the leg of the coil. (Basicly

you're adding 1/2 of a turn to the coil when you do this). It used to point

towards the inside of the mold, now it should point to the outside. Then

take the inside of of the same coil and bend it around the island in themiddle of the mold to the next radial line in the mold, and cut it off

about 1/2" past that line. This wire will connect to the end of the next

coil, and the start of that coil will need to connect to the end of the

last coil in that phase. So what your doing is making sure you have just

the right amount of wire to connect the coils and cutting off the excess.

It's better to be a bit on the long side than a bit on the short side so

give yourself a little extra length to be sure - but not much because

there's not much room for wire on the inside of the mold. Once this is

done to three coils you have 1 phase ready. Repeat this for the next two

phases.

71


72/187


73/187

Put the 3 coils back in the mold and twist the wires together tightly.

You can see in the picture how the connections are pretty much centered

in between the coils. Then solder the connections, and bend them over with

pliers so you can insulate them with electrical tape and keep it all as

thin as possible. You can also use heat shrink here for neater appearance

- if you do, be sure to put that on before you twist the leads together!

73


74/187

If you're building a 12 Volt machine with multiple strands of wire it can

be tricky to twist things together nicely. For machines that have multiple

strands, it works well to make your connections by inserting the coil leads

into small copper, or brass tubing - and then crimp and solder.

Once you have one phase connected together, carefully remove it from the

mold and do the same thing to the other two phases.

Once all three phase are finished, put all three back into the mold as

shown in the picture. Do it such that your three 'ends' (those wires that

are pointing towards the outside of the mold) are beside each other. Those

three 'ends' will be the leads out of the stator (the output from the wind

turbine).

74


75/187

Now you need to make the star connection between the phases. The 3 inside

leads should be brought together so that we can connect them together.

Leave enough slack in the wires so that we can make this connection, and

then push it down between the coils and the island in the mold. So figure

the length, cut them off, burn the insulation with the torch, sand it,

twist them and solder them. Then insulate the connection with electrical

tape or heat shrink.

75


76/187


77/187

Cut 9 little rectangles from fiberglass cloth about 1.5" wide and 2" long.

Before you cast the stator you'll need to remove the coils from the mold

again. We'll use these squares of cloth and superglue to hold everything

together so that we can move it.

Use the cyanocrylate glue to glue the fabric rectangles to the legs ofthe coils. Put plenty in - you'll know its a good glue joint when the cloth

77


78/187

becomes transparent. This will also serve to somewhat 'pot' the legs of

the coils and prevent individual wires from vibrating against one another

- maybe not an issue, but I like to have lots of superglue in the coils.

Also put glue on the fabric between the coils so that the fabric becomes

'hard' and less flexible. This will make the stator fairly rigid and easy

to handle before you cast it. Try hard not to glue the coils to the mold!

In the picture you can see all the coils are connected to one another with

fiberglass cloth.

78


79/187


80/187

Casting the stator

The stator will be cast in the same polyester resin you used for the magnet

rotors. You'll need fiberglass cloth on both sides of the coils. It might

be useful to reveiw the section on casting magnet rotors before doing this

as the proceedure is very similar and safety precautions are the same.

80


81/187

If you fold the fabric correctly, you can lay out just 1/4 of the ring

and cut out two in one shot. You need two rings of fiberglass 15" outer

diameter and 6" inner diameter.

In the picture you can see the two rings of fiberglass. Set them, and the

coils aside for now. Grease the stator mold inside, on top - and around

the edge. Same with the lid - everything should be carefully covered with

grease, or wax. Automotive or wood wax works really well.

81


82/187


83/187

Put one of the fiberglass rings into the resin and work it with a stick

untill it becomes saturated. When saturated - the fabric will become

almost invisible. (you won't see any white)

Then pour about another pint of resin in the mold, work it into the fabric

more - try to work out any airbubbles.

83


84/187

Put the coils in carefully, poke at them so resin runs all around the coils

and airbubbles come up.

Then fill the mold with resin and be sure all surfaces of the coils have

resin on them.

84


85/187

Put the remaining fiberglass ring over the top of the coils and work resin

into it - again, it should almost disappear.

Pour the remaining resin over the top of the fabric. Work it in and try

to work out air bubbles. It might not hurt at this time to beat on the

mold a bit or vibrate it with a sander (or something) for a couple minutes

to help air bubbles rise to the top.

85


86/187

Carefully put the lid of the mold down over the casting.

Put a 1/2" washer over the threaded rod, and run the 1/2" nut down over

it. Tighten the nut - this does a good job of clamping the lid tightly

on the mold and assuring that the finished casting will be 1/2" thick.

86


87/187

Put a C clamp on each side of the mold (use 4 C clamps) and tighten them

evenly. You'll have some idea when the resin is hard by all the stuff that

spilled out the side! Let the stator sit in the mold untill the resin is

hard.

A chisel works well to scrape/peel the resin off around the outside of

the mold. A good time to do this is while it's still a bit flexible (before

it gets really hard).

87


88/187

Once the resin seems hard then remove the C clamps and the nut in the center.

Use a chisel or a screw driver to gently pry around the lid untill it breaks

loose.

Once the lid comes off you can usually turn the mold upside down and the

stator will just fall out. If not then turn the mold upside down and tap

88


89/187

on it with a hammer or pry gently at the edge of the stator. It should

come out easily.

Use a file or a sander (or both) to clean up the edges of the stator. The

inside diameter must be pretty clean because there's not a lot of extra

room between this hole and the wheel hub which will exist inside it.

89


90/187


91/187


92/187

The stator is finished! We can put that aside untill we're ready to

assemble the alternator.

The Mold

The alternator requires two rotors to be built. The first step is to build

a wooden mold. Each rotor will be made from 12" diameter steel disks each

with 12 magnets on it. Once we've built the rotors we'll cast polyester

resin around them to keep the magnets in place and prevent corrosion. In

order to make a neat casting we need to build a mold out of plywood. Like

many other things in these plans, there are alternative ways of doing

things. Here we'll detail exactly what we've done. Some of the pictures

show two molds in use, but you only need one. See the picture above for

dimensions of all the parts

Materials list- 3/4" thick plywood, 2 squares 14" x 14" - 1/2" thick plywood disk, 6.5"

diameter - 1/4" plywood, 1 disk 2.75" diameter - about 20 1" long wood

screws

92


93/187

The mold is 14" square. The hole in the center is 12.5" in diameter and

3/4" deep. In the center is an island 2.75" diameter and 1/4" thick. The

lid is the scrap which we cut from the center of the mold (a 12.5" diameter

disk). The center of every part has a 1/4" hole drilled through the center

that we use to align everything during assembly. All the disks are easy

to cut out with a bandsaw, or a jig saw. With some patience a coping saw

would do fine as well. All the disks and the inside of the top that we

cut out should be sanded smooth, and preferably slightly tapered so that

the top of hte hole is slightly larger diameter than the bottom. Once all

the parts are cut out, screw the 3 square pieces together so that the one

with the 12.5" diameter hole is on top. The screw the small 2.75" dia disk

down in the center - using the 1/4" drill bit as a pin to center it perfectly.

Caulk all the seams inside the mold so that resin can't run into cracks.

This, the sanded surfaces, and the tapered hole in the mold will make the

molded pieces easy to remove.

The magnet template

93


94/187

The next tool you need to make is a template for placing the magnets. The

one pictured was made at a local machine shop with a CNC water jet cutter

out of 1/8" thick aluminum and the cost was quite reasonable (about $25

USD). But you can just as well build it from thin plywood or plastic. It's

a 12" diameter disk, with 4 1/2" holes on a 4" diameter (just like our

magnet rotors) and 12 equally spaced cutouts the size of our magnets (1"

x 2" x 1/2" in this case). We do sell CAD-cut aluminum templates that are

perfectly aligned for this -- check our online store.

Building the magnet rotors

94


95/187

Materials- 12" diameter mild steel disk, 1/4" thick, qty 2 - 1" x 2" x 1/2" N35

grade NdFeB magnets, qty 24 - cyanocrylate glue with accelerator -

fiberglass cloth or mat, 2 square feet - 1/2 gallon polyester resin

Start with two steel disks, 12" diameter. Each disk should have 4 1/2"

holes on a 4" diameter circle(a touch larger to provide some clearance

is nice) and a 2.75" hole in the center. You can build a rotating table

and do a pretty neat job cutting these out with an oxy-acetaline cutting

torch, but we usually have ours cut out by a fabrication shop. A CNC laser

cutter, plasma cutter, or water jet cutter will do a very nice job. If

you have it done, you might have them cut all the holes for you - it saves

a lot of time and assures that things are accurate. Otherwise, if youdecide to machine your own rotors, the first step is to cut a 2.75" hole

in the center of both rotors. Use a high quality bi-metal hole saw and

a drill press for this. The drill press needs to be run very slowly and

you need to use lots of oil. Easiest is to clamp both rotors together and

cut both at the same time. Save the scraps from the center, we can use

one of those later. Next, keeping both disks clamped together, drill out

the 4 .5" diameter holes equally spaced around a 4" diameter circle. The

easiest way to do this is to put the wheel hub on the rotors and clamp

it there, and drill right through the holes on the wheel hub. This saves

a lot of layout and assures accuracy. One of the disks needs 4 more holes7/16" dia (also spaced around the same 4" diameter and located between

95


96/187

the .5" diameter holes we just finished) which we'll tap 1/2" - 13 for

jacking screws to aid in the assembly/disassembly of the alternator. Again

- we usually have this done at a fabrication shop - when they cutout the

disks for us it's easy for them to use the same CNC machine to make all

the holes.

Pictured above we're tapping the 4 smaller holes 1/2" - 13. It's important

to use lots of oil (or tapping fluid) when running the tap in. Try to keep

the tap as straight as possible. Once it starts to cut threads, turn it

just till things start getting tight, then back up a bit and 'break the

chip'. Continue this untill the tap goes all the way in and spins freely.

Never force the tap in if things get too tight - always back it up, break

the chip and then go foward again.

96


97/187

Use a countersink to chamfer the edges of the 1/2" diameter holes. This

makes things assemble more easily and helps protect the threads on the

studs that hold the alternator together. Once this is done, all the 'metal

work' is finished for our rotors. Both rotors are oily (finger prints and

oil from drilling and tapping) so we need to clean the carefully with some

kind of solvent. We usually use laquer thinner. After that - try to keep

grease off them, handle them with clean hands. You're about to start

putting magnets on them, so this is a good time to clean the work area.

Metal chips from the drill press and grinder should be cleaned up, or you

should move the work to a new cleaner environment.

97


98/187

The steel disks don't always come out perfectly flat. I expect some sheets

of steel get bent in handling by forklifts and such and when the disks

get cutout sometimes we find them slightly warped. Check for this with

a straight edge. Flatening them can be done but it's tricky. We usually

locate the dimension in which it's warped and we put our magnets on the

most convex surface. (the surface facing up towards the straight edge in

the picture is the surface we'd put the magnets on)

98


99/187

Put the magnet template down on one of the steel disks and line the holes

up.

Place the other steel disk down on top of that, with the holes line up

and pin the sandwich together with two 1/2" drill bits (or wooden dowels

or bolts or whatever).

99


100/187

Looking from the side you can see the 'gaps' in the template where the

magnets will fit. Pick one gap and use a permanant marker to mark both

sides of the gap. This is where we'll place the first magnet on each disk.

(drilling into the top magnet rotor)

(drilling into the bottom magnet rotor)

100


101/187

Use a small drill bit (3/16" is a nice size) and drill a divit (a dent

- not a hole, don't drill through) into both disks between the marks we

made. These will be on the outsides of the magnet rotors and will serve

as 'indexing marks' so that when we assemble the machine we'll know how

to line up the two rotors. Alignment of the rotors is critical in the

operation of this alternator, they must always go together the same way

with alternating magnetic poles facing one another. Once we've done all

this we can take the top rotor back off the stack and put it aside in a

safe place (away from the bottom rotor because were about to play with

magnets).

For this alternator we require qty 24 Grade 35 NdFeB magnets 1" x 2" x

1/2" thick. These are available from many vendors, they usually come

either epoxy coated or Nickel plated, either way is fine. These are very

powerful magnets and need to be treated with extreme focus and caution!Two coming together on your finger could hurt very badly and leave blisters

easily. Once we assemble these on the rotors we have some very

powerful/dangerous magnetic assemblies. Two finished magnet rotors

coming together on your fingers could easily break them! Build one magnet

rotor at a time. When it's finished- put it in a safe place. When building

these be sure that all ferrous (anything containing iron which includes

steel tools, wrenches, knives scissors etc) are away from the work area.

Only handle one magnet at a time and always grip them firmly. If a magent

flys onto a piece of steel or into another magnet at high velocity, it

may break and send shards flying! Handle one at a time, handle them with

101


102/187

a firm grip. Store them in a safe place away from kids and folks who don't

realize what they might be getting into. Keep them away from

electronics/video tapes and other forms of magnetic storage medium. These

magnets are perfectly safe when handled properly, but most folks are not

familiar with the dangers and there can be surprises.

The magnets are so strong they can be tricky to seperate off the stack.

The best way is to place the stack on a wooden workbench and hold the stack

firmly. Then grasp one magnet firmly with the other hand and slide it off.

(you'll not be able to just pull them apart, you have to 'shear' them apart)

102


103/187

Now we can place the first magnet on the bottom magnet rotor. The template

is pinned to it and made of wood or Aluminum so it won't move. But the

magnet is strongly attracted to the steel disk so we need to hold that

down with one hand. While firmly gripping the magnet in the other hand,

bring it towards the edge of the rotor and 'slide' it into the slot. (don't

just try to put it down on - it will pull out of your hand and hit the

rotor hard - possibly breaking the magnet!)

103


104/187

The magnets need to be spaced around the disk with alternating poles facing

up. All magnets have two poles, a North and a South. Opposite poles (North

and South) attract one another, like poles repel. It doesn't matter how

we put the first magnet down so long as things alternate from there. The

safe way to place the rest of the magnets is as follows: Hold the magnet

rotor down firmly to the work bench with one hand which should be placed

over the magnet that's next to the one you're about to place. Then, holding

the next magnet firmly, bring it over your hand which is holding down the

rotor. If the bottom of the magnet in your hand is repelling the one on

the rotor, then slide it into the slot carefully in it's current position.

(Because we know that if the bottom of the one in your hand is repelling

the top of the one on the rotor then we have like poles facing each other,

so the one in your hand has the opposite pole facing up as the one on the

magnet rotor)

Once all the magnets are placed on the first rotor you can remove the pins

and pry the template off. Do this carefully so the magnets don't slide

around.

104


105/187

Run a bead of thin viscosity cyanocrylate glue (Super Glue) down both sides

of each magnet. Large bottles (2oz usually) are available at most hobby

stores. It's also handy to have 'accelerator' which will force the glue

to harden immediately. The accelerator usually comes in a small spray

bottle. We don't rely on this glue to hold the magnets down forever, it's

a temporary means to keep things in place till we finish the casting. If

cyanocrylate glue is not available then other glues should also work fine.

Epoxy would probably be fine it just takes longer to dry.

105


106/187

I expect you could skip this part all together, but I believe it offers

some insurance that our magnets will never fly out. Also - if the resin

cracks this will keep things together for us. Take a roll of fiberglass

drywall tape (this stuff is sticky on one side) and cut the roll with a

razor knife so that you can peel off a strip of the tape about 1/2" wide.

106


107/187

Wrap the tape around the magnets several times. Be sure that none of the

tape sticks up above the top of the magnets.

Now that the first magnet rotor is finished, drive a nail somewhere in

a wall in a high/safe place and hang it there. It's a somewhat dangerous

thing and should be kept in a safe place.

107


108/187

Now to begin the second magnet rotor. Put the template on it so that the

4 holes line up and one of the slots lines up with the marks we made earlier.

This assures us that the magnets we place will be facing each other when

the rotors are assembled. The top of the first magnet on this rotor must

be the opposite pole as the top of the first magnet we placed on the first

rotor. In other words, the two surfaces facing one another must attract

one another. Once you get the first magnet down, follow the same proceedure

as you did with the first magnet rotor.

Check your work!You can easily double check your work now. Find a small magnet and hold

it in your hand (dont turn it over - hold it in the same position always

for the testing). Each magnet rotor has one magnet (the 1st one we placed)between the marks we made. The test magnet should attract this magnet on

one magnet rotor, and repel it on the other. Then we can go around each

magnet rotor and the test magnet should attract one magnet, repel the next

one, attract the next one etc. If you made a mistake, you need to knock

loose the offending magnets, put the template back on and get them right.

Once all the magnets are placed and the tape is wrapped around them it's

a good idea to clean the magnets and the rotors one more time with laquer

thinner to make sure there's no grease. This will help the resin stick

to the magnets.

108


109/187


110/187

you use the mold. The first coat tends to soak into the wood but after

several applications it gets better. The point here is to make the mold

greasy so the resin won't stick to it. Once all the parts are greased well

then run a bead of caulk around the outside of the 12.5" hole in the mold.

Also run a thin bead around the outside of the 1/2" thick 6.5" diameter

disk. If it's not still there, stick the 1/4" drill bit in the center hole,

we'll need this for alignment.

Drop one of the magnet rotors into the mold carefully. It fit nicely on

the smaller 2.75" disk in the center of the mold so that the magnet rotor

is a good fit and about pefectly centered.

110


111/187

Put the 6.5" diameter disk down. The drill bit will serve to center it

on the disk. The side that we've run caulk around should face down and

we need to press it down onto the magnet rotor. The caulk will assure that

no resin can run under it.

We use polyester resin to cast the rotors. We get this stuff from almostany autoparts store. It's best to buy it by the gallon (it takes about

111


112/187

exactly one gallon to build this whole machine). It comes with hardener

in small plastic tubes.

It's nasty stuff. It smells bad, the fumes are toxic. Best to work outside

or in a very well ventelated area. Use safety glasses (the hardener is

especially dangerous if you get it in your eyes), rubber gloves, and a

respirator.

112


113/187

It takes almost exactly 1 quart of resin to make 1 magnet rotor. (maybe

a touch less) Usually a gallon of the resin comes with two tubes of hardener,

each containing .77oz (22ml). When casting this stuff the resin tends to

warm up and get hard much faster than it would in normal applications -

especially if its warm outside and if the resin is warm to start with.

We usually use about half the hardener that the instructions call for.

This lets it harden more slowly - I believe it helps it to be stronger,

shrink less and make things less likely to crack. There have been times

when we've used half the tube for 1 quart (what the instructions call for)

on warm days and the resin has become hard in 15 min or less! (it was hard

before we could even pour it!) If it goes off too fast, there is also the

risk of it catching fire. So be careful...

If you like, there are powders available to color the resin, or you can

just use a little bit of acrylic enamel to give the resin a color. If youuse enamel, I would use about 1 part paint to 50 parts resin.

Pour resin into the mold and over the tops of all the magnets. The mold

needs to be level and it should be completely filled with resin.

113


114/187


115/187

The lid also has a 1/4" hole in the center. Place it down over the drill

bit and on top of the magnet rotor. You can clamp it down with magnets,

or bits of steel (wrenches etc..) because they'll all stick to the magnets.

C clamps are fine too but more work than necessary. Keep an eye on the

resin that spills out of the mold. When it starts setting up clean the

outside of the mold. Don't take the lid off though untill you feel the

resin is good and hard. In practice, depending on the tempurature and the

amount of hardener we used I find this takes anywhere from 1/2 hour (which

is scary fast - I expect cracks and shrinkage when it goes that fast) to

24 hours. It seems the slower the better with regard to shrinkage and

cracking.

115


116/187

Once the resin is completely setup we can remove the lid from the mold.

Usually (if we made the mold well and greased it well) the rotor will just

fall out of the mold when we turn it over. If it doesn't, tap it on the

back with a hammer and it should. Sometimes things get tricky and we have

to pry it out, or even take the mold apart but this shouldn't happen if

we did everything correctly. The wooden disk on the inside of the rotor

should knock out easily with a hammer through the hole on the back side

of the magnet rotor. The edges of the rotor will be rough. We can cut the

excess resin off with side cutters - or remove it with a sander. A belt

sander works real well, but be sure to wear a dust mask. Clean up all the

burrs so that nothing sticks up beyond the surface of the magnets.

116


117/187

There we have a finished magnet rotor! Once one is finished - then repeat

the process with the second one in the same mold. We actually use two molds

(molds are easy to make) so that we can get all this done in one shot but

if you're not in a rush one at a time works fine.

It's only for cosmetic reasons and not important at all... but if you havea lathe available that's large enough it's fun to clean up all the edges

117


118/187

that way. If you do, be careful and remember how feircely these rotors

are attracted to steel. When cleaning up edges or deburring on the lathe,

*DO NOT* use a steel file. Use sandpaper. A small flat sanding block is

a handy tool on the lathe. A file, or any other steel tools that are not

'part' of the lathe should be kept away because of the magnets. I've seen

magnets yank steel tools out of peoples hands on the lathe, it can be very

dangerous. Again, this step is not needed - one does not require a lathe

to build this wind turbine, it just makes things look nice. to return to

the front page of this project.

This page details how we assemble our alternator from all the finished

parts. At this point we've completed all the metal work and it's been

painted. The magnet rotors and the stator are finished, and we're finally

assembling the machine.

Pictured above are the finished magnet rotors. They are identical, except

that the front rotor (closest on the left in the picture) has 8 holes,

4 for the studs, and 4 for jacking screws which will allow us to lower

it safely and raise it back off the alternator if necessary. Each rotor

also has a small mark (a divet made with a drill bit) so that we can align

the two rotors properly.

118


119/187

Here is the main chassis for the machine all painted and ready for assembly.

It's handy to have a stand so we can turn it around/position it for easy

assembly.

Pictured above is the wheel hub, bearings, washer and nut. Not pictured

is the cotter pin. Typically when we order the hub, we get the bearings.The washer, nut, and cotter pin comes with the spindle. The hub is Dexter

119


120/187

part number 81- 9A, and the spindle is designed for this hub, but they

are always sold seperately. Most trailer parts supply houses can provide

this. I like the Dexter hub because it seems to be the most common one

available, and it comes machined on both sides. Many hubs are machined

only on one side which makes assembly more difficult. If a different sort

of hub is used, I expect that the lengths of our allthread studs would

change, and you may find the need to use extra shims to set the airgap

between the magnet rotors properly. With this hub, things are very easy.

When delivered, the hub has 4 studs pressed into it (this is to accept

the lug nuts that hold a trailer rim on). We need to knock those out with

a hammer. It goes quite easily.

120


121/187

Pictured above is all the hardware required to assemble the machine except

for the bolts/nuts that hold the tail on. I prefer to use all stainless

hardware so that it can never rust, but this is optional except for thehardware that is near the edge of the magnet rotors that holds the stator.

We will be relying on nuts and lock washers to act as 'spacers' between

the magnet rotors, so it is important that we use fairly high grade

hardware and make certain that all the nuts/washers that are used between

the magnet rotors are the same height. I find that with cheap hardware

this is not always the case, with stainless hardware it usually is. Here

is a list of hardware:

1/2 - 13 nuts, qty 25 1/2 - 13 acorn nuts, qty 7 (we could use normal nuts instead - acorn

nuts just look neat)

1/2 - 13 allthread 6.625" long, qty 4 1/2 - 13 allthread 4" long, qty 3 1/2" lock washers, qty 18 1/2" washer, qty 6 (I use the smaller AN style and they must be

stainless. If we need to shim the airgap wider, we may require more

than 6 of these)

121


122/187

These are the steel hubs we 'sandwich' the blade betwen. They are 6"

diameter with 4 holes on 4" diameter to fit our Dexter hub. The one with

the hole (2.75") goes behind the blade, the other one goes in front of

the blade. I show these now because they (one of them) come in handy when

assembling our alternator. Otherwise we'll not use them till we install

the blades.

122


123/187

Before we assemble the alternator it's important that the magnet rotors

be clean. Often times while building these we find that bits of

metal/grindings get stuck to the magnets. They lay pretty flat on there,

but when we assemble the alternator (put the two magnet rotors on facing

each other) all the chips will stand up and rub on the stator. We need

to clean it now. A good way to remove metal chips from the magnet rotors

is with duct tape.

The first step is to take the 4 pieces of allthread which are 6.625" long

and put one nut on. We screw the nut down on one end so that there is 7/8"

of allthread behind it.

123


124/187

Then we put the long end of the allthread through the backside of the wheel

hub. Put on a lock washer, and another nut and finger tighten the allthread

to the hub (no need to get things tight here - just finger tight is what

we want). Do this with all 4 studs, and then run a nut onto the front of

each stud so that about 1/4" of allthread is protruding. So, if we look

at one stud here starting at the front (left to right in the picture) here

is whats important: 1/4" of allthread, 1 nut, more allthread, a nut, a

lock washer, the wheel hub, a nut, and then 7/8" allthread.

124


125/187

We take the back magnet rotor (the one with only 4 holes) and turn it so

that the magnets face down on the bench. (be sure the bench is clean from

metal bits)

Take the back of the hub and put it into the hole in the magnet rotor,

such that the ends of the studs (the ends that are 7/8" long) are pokinginto the 4 holes. We do this to align things before we tighten anything.

125


126/187

Then we use one of the steel blade hubs (the ones above that are painted

black) and place it over the studs on the top and it should come to rest

on the 4 nuts that we put up there. (thats why we put those nuts there

with 1/4" of allthread sticking out). If we don't have these blade hubs,

we could use the front magnet rotor, I would do it with the magnets facing

up so that we can tighten things without worrying about magnets grabbing

our wrenches. If we do it this way with something to align our studs both

at the top, and the bottom - we are fairly assured that the studs are well

aligned and everything will fit together nicely.

126


127/187

Now we can tighten the nuts on both sides of the wheel hub. We should get

them very tight, and the goal is to move only the top nut (the one with

the lock washer under it) and not the bottom one, so that we are sure to

have 7/8" of allthread behind the back nut.

127


128/187


129/187


130/187

On the back side of the magnet rotor each stud gets 1 lock washer and 1

nut. We can tighten these a bit with a wrech now, but it's easier to really

tighten these ones after the alternator is together.

130


131/187

Now we can grease our bearings. Press lots of grease into both bearings,

work the rollers around for a while and be sure the bearing is well greased.

The front and back bearings are identical for this wheel hub. Put one ofthe bearings on the wheel spindle and push it back all the way. It's

131


132/187

probably a good time to mention... usually when you order a hub, it comes

with a seal. We do not use the seal in a wind turbine, it creates too much

friction and prevents easy startup. I believe if we grease the bearing

well then they should be fine for quite a long time.

Carefully pick up the hub/back magnet rotor by the studs and place it onto

the spindle, up against the back bearing.

132


133/187

Then insert the front bearing. Usually at this time I press a little more

grease into the front of the bearing... can't hurt.

The place the washer in front of the bearing.

133


134/187

Then tighten the nut over the bearing. Get the nut reasonably tight, and

then back it off so that you can insert the cotter pin.

EOLIAN GEN DIY.pdf

Documents

Transcript of EOLIAN GEN DIY.pdf