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Bigger machines?
By hvirtane, Section Wind Posted on Wed Nov 24, 2004 at 01:08:03 PM MST
It is possible to make 10 kW wind turbines yourself

Some of the 'old' experienced guys here
have built quite big wind turbines.
They are using them for heating
purposes.
I think that the biggest challenge
is to make big blades. The rest of
the machine is simpler.
It is maybe
easiest to use a gearbox and a
standard generator.
However, I think that it is as well
possible to make even a 10 kW direct drive
generator yourself either by an induction
engine conversion or by using the axial
permanent magnet generator approach.
Two approaches for big blades.
Tube wire blades.

These blades are waiting for a reinstallation.
They have been in use for 6 years without
any problems in Finland. They were designed by
Kyösti Juvonen and built by him and by Risto Ruppa. The dimensions of the blades are in
the next picture.

The blades are built with a tube wire method.

The tube inside the blade is tapered.
The fixing system of the blades is made
really strong.

Blades of wooden strips.
The idea for these blades comes originally from
a man called 'Reinikainen'. Here is a picture
of one of his original machines. The rotor is
7,5 m in diameter.

This machine has been in use for more than ten
years in Finland. At the tips of the blades
there is coating with fiberglass. The blades are
made of wooden boards.
We have later made some experiments with that
system of building the blades. With Taisto
Suihkonen we have made a wind rotor of
3 m diameter with four blades. Taisto made
an experimental airfoil for those blades.
More details about those blades in my diary.
http://www.fieldlines.com/story/2004/6/2/163021/1860
We made also with Erkki Nousiainen
a quite big set of blades with a similar
design. The diameter of these blades
is 10 m. The rotor is with two blades and
we made on the tips of the blades an airfoil
according to the airfoil shape K2 as published
by Hugh Piggott.
Partly the idea to make the blades
wider on the tips is based on the GGS
theory by Gorlow and others (besides
the easiness of the construction). According
to the GGS theory the air is flowing
towards to the tips of the blades,
so it might help to make the tips wide...

Here is a picture of the blades under
construction at the workshop of
Erkki Nousiainen.

Another picture of the blades
under construction to show
the idea how to get the airfoil shape.
The blades are now flying up there
on the tower. The rest of that wind turbine
is a quite old construction originally with
a pitch control system, which is not
in use at present.
I will post some pictures of
the complete wind turbine,
when got them from Erkki
or from other friends.
In principle and in practice
the blades seem to
be working well, but I have
no measured figures yet.
- Hannu

Bigger machines? | 12 comments (12 topical)

Re: Bigger machines? (3.00 / 0) (#1)
by phil b on Wed Nov 24, 2004 at 01:20:56 PM MST

Hannu,
Can you post the specifications on the wooden strip blades?

Re: Bigger machines? (3.00 / 0) (#5)
by hvirtane on Wed Nov 24, 2004 at 02:24:01 PM MST

I will try to visit Erkki Nousiainen
tomorrow or on the next day.

We should now also start experimenting
with the generator. With that machine
there is an induction generator,
which needs some 'flashing of the field'.

I will try to get some more pictures from him.
The design of the blades was mainly mine,
but he made them almost alone. I told
him frequently to take pictures during
the construction. I hope that he has
got pictures.

- Hannu

[ Parent ]

Re: Bigger machines? (3.00 / 0) (#12)
by hvirtane on Thu Nov 25, 2004 at 09:56:39 AM MST

For the construction of the blades
standard wooden boards were used.

Originally the drawing was for eight boards.
Finally Erkki added one more board to
get the shape of the leading edge good.

The boards were glued together using
water resistant high quality glue.
The basic idea is to make a kind of fan
of the boards.

A picture of the basic idea.

A picture of the simple gluing
method Erkki used.

In this drawing my original design is
explained. On the tip the shape is
according to K2 airfoil. In the drawing
it is shown, how the shape of the airfoil
changes toward the root of the blade.

On tip the width of the blade is
about 40 cm. Contrary to the
conventional design the blade
is narrower at the root.

For fixing the blades on the
nacelle, steel boxes were used.
In this picture the constructor
Erkki Nousianen is showing
the fixing system he made.
He added more length for the box
using thinner steel plates.
The box is bolted on the nacelle/axle.

The length of the blade is 5 m
so that the diameter of the wind rotor
is about 10 m.

The wind turbine is of down wind type,
originally with a pitch control system,
which is not in use at present.

There is a gearbox with 1:16 gearing.
The generator is of induction type.

I will still later publish some
pictures of the complete turbine
and the tower.

I'm in agreement with the others
that most of the problems are
quickly getting bigger, when
we are increasing the turbine size.
The towers are becoming really
costly with bigger turbines.

But on the other hand,
if you are trying to make
energy for heating,
you need several kilowatts?

- Hannu

[ Parent ]

Re: Bigger machines? (3.00 / 0) (#2)
by skravlinge on Wed Nov 24, 2004 at 01:30:16 PM MST

I think this is new for some, in fact many blades in Scandinava are are build like this. The early but later successfully danish wind power industries have or maybe still use it. With an induction generator and speed control is it like a grid connected bigger plant, and have very much to learn small builders. I have seen places with four windmills , which could be better off by one bigger (easy to understand). The design is maybe not so easy as cutting wood, but in larger sizes this is very good if you count weight to ability to stand forces.
-- Always find the typos after posting!

Re: Bigger machines? (3.00 / 0) (#3)
by juiced on Wed Nov 24, 2004 at 01:37:12 PM MST

dont forget about the helicopter mill..

Canada's -Debatable- A.E./R.E Debate Site
News, discussions and debates!
www.juiced.ca

Re: Bigger machines? (3.00 / 0) (#4)
by iFred on Wed Nov 24, 2004 at 02:19:49 PM MST

Bigger machines are

harder to create
more expense to create
more expense to create (yes I said that twice for a reason)
requires more manpower to install
did I mention expense?

And if something does go wrong it's going to go wrong big time. besides which, if it breaks down you loose it all.

Lately I have been thinking in smaller gennys since they, cost less, are less costly to maintain, require less resources and manpower and you can create lots of them and if one breaks down the rest are still working..

But thats jsut my oppinion, after of course building a big one, the expnse is killing me, so is the time invested and the materials required.
>> all energy used to produce this comment or post came from solar and wind energy! It works!

Re: Bigger machines? (3.00 / 0) (#6)
by windstuffnow on Wed Nov 24, 2004 at 04:02:51 PM MST

I've been preaching small turbines for years, I agree iFred. 3 of my 6.5 ft turbines will make 2.5 kw. Cheap, simple to build, and redundancy is the key. If one goes down I'm still making 1.6 kw. Unfortunately, I didn't have time to get the other 2 up this year. But the single is doing good so far although not as much power as I'd like to see comming in. Was only getting 35-45 amps today, does the job but just barely.

Havin' fun as usual

My waste engine is getting closer to final assembly so that will offset the 2 missing turbines...

Windstuff Ed

Have Fun! Windstuff Ed
[ Parent ]

Re: Bigger machines? (3.00 / 0) (#7)
by richhagen on Wed Nov 24, 2004 at 04:28:24 PM MST

Ed, Since you've built and flown machines both ways, how do you compare the wave wound stator your flying now with a stator made of individual coils. Rich Hagen
'A Joule saved is a Joule made'
[ Parent ]

Re: Bigger machines? (3.00 / 0) (#10)
by skravlinge on Thu Nov 25, 2004 at 12:00:31 AM MST

All facts says a bigger is cheaper by KW/h. There is exceptions for the very small machines such most of you here make. DYI parts can be easier and cheaper in a lower scale. The wind-rose on the place can show a small machine will be more economical. But in general a bigger machine is cheaper by KW/h. A new 32 KW cost not double than a 64 KW and a 500KW cost not double than a 1000 kw.
-- Always find the typos after posting!
[ Parent ]

Re: Bigger machines? (3.00 / 0) (#8)
by richhagen on Wed Nov 24, 2004 at 04:34:55 PM MST

Nice post, I hadn't read your diary until today, good explanation/diagrams of three phase alternator wiring connections there. Keep having fun, Rich Hagen
'A Joule saved is a Joule made'

size matters (3.00 / 0) (#9)
by wdyasq on Wed Nov 24, 2004 at 06:43:00 PM MST

Having worked on several mills of varying sizes, I will state the problems go up with size. The smaller mills used off the shelf components. There were things that could be used to measure power output and most were available at local industrial supplies in any major city. As the machinery got more powerful, so did the problems and searches for solutions.

I've seen the same scale and types of problems on go-carts to Can-AM racers and scooters to 170 true MPH motorcycles. The scale of costs goes up with the square of speed or power it seems. The 'will work' sprocket on a 20 mph go-cart becomes an expensive gear in a Can-AM car that has to be made.

One must also put in the cost of tower and support equipment. While a 30 foot tower can be hand-raised by several strong fellows with genny attached, a 60 foot tower and mill with 16' of blades and such needs more gear. And, the towers are part of the cost of the mill, as is the wire, rectifiers, batteries and electronics. All of these go up in a scale that is not linear with power output.

I've had discussions with several and it is our thoughts about 5kW is the limit for a self-build and raised mill. This mill will have 22-28 foot blades depending on wind conditions and still could be built in a good-sized 'home shop'. Still, the variety of skills needed would be a challenge for one man to master all of them.

Ron
Adventure is just bad planning." -- Roald Amundsen

Re: Bigger machines? (3.00 / 0) (#11)
by domwild on Thu Nov 25, 2004 at 12:29:58 AM MST

Hannu,
Great photos! I am impressed and have seen your photos before of the "wire props" but not the wooden ones. I am also impressed with another country man of yours, a Finn selling those hollow-core alu props, however, the euro 400 price tag was a bit too steep for me!

dominic
dom We only ever use the best fencing wire for our repairs!

Bigger machines? | 12 comments (12 topical)

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