Author Topic: 180 volt 3.2 meter turbine  (Read 21752 times)

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Offline ChrisOlson

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Re: 180 volt 3.2 meter turbine
« Reply #45 on: March 04, 2012, 12:55:52 pm »
Things tend to favor gearing when the size exceeds 20 feet or so. Or seems to anyway.

Gearing is more common in 20 foot and larger.  But Wincharger used it on machines down to 6 feet in diameter because neo magnet technology didn't exist back then and they needed speed to get their 6 volts.

I can be practical anywhere you get gains in overall efficiency by using it.  The gains might be economic - magnet and copper cost vs cost in the gearbox.  They might be electrical - better power efficiency while taking a "hit" in gearing vs a direct drive.

There are always going to be folks that proclaim direct drive as "the only way", and I assume those folks own cars with the engine strapped sideways in the trunk with a tire bolted to each end of the crankshaft.  It all depends on the application and the design.  For a small 10 foot turbine like this on a direct hooked battery charging configuration I suspect it would be hard to justify a geared mill.  For a high voltage application where I can live with a few losses in gearing to get greatly enhanced output it pays off.
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Offline ghurd

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Re: 180 volt 3.2 meter turbine
« Reply #46 on: March 04, 2012, 06:45:05 pm »
I think "K.I.S.S" trumped everything there?
Simple is good but only if it works and works long term.
Not even remotely capable of a transmission build myself.

Yes. KISS. And KISS works.
Not many people can build a "works long term" transmission, leaving KISS.

For a small 10 foot turbine like this on a direct hooked battery charging configuration I suspect it would be hard to justify a geared mill.

and

Really, I don't know who came up with the theory that geared mills are "bad".
There's a lot of "old wive's tales" that seem to get propagated as "fact".

And that perspective is Exactly where it came from!

Just a few years ago, before your time in the discussions, 4' was small, 6~7' was big, and 10' was huge.

Now, 4' is a toy, 6~7' is tiny, and 10' is small.

A 10~20~50 year old book is going to have a different perspective of something small or large, and DIY.
When neos did not exist, or when neos and copper were cheap, the perspective will be different.
Apples : Oranges

(my uncle used to brag that his pickup truck got 11MPG)
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Offline frackers

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Re: 180 volt 3.2 meter turbine
« Reply #47 on: March 04, 2012, 07:07:47 pm »
Looking purely from the perspective of using what is available, would it be viable to use a cam chain and sprockets from something before the era of the cambelt?

The sprockets on the (small) engines I have experience of would generally have the cam sprocket on the flush end of the camshaft but the crankshaft end would be through hole with a key or splined.

Just making a mind exercise working backwards from the items maybe available from the local scrap merchant!!
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Offline ChrisOlson

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Re: 180 volt 3.2 meter turbine
« Reply #48 on: March 04, 2012, 07:29:31 pm »
Looking purely from the perspective of using what is available, would it be viable to use a cam chain and sprockets from something before the era of the cambelt?

I suppose it could work.  But you only have one gear ratio option with that - .5:1.  The crank sprocket is keyed and usually has a non-standard bore size, which is going to require machining a shaft to fit both the bearings and the sprocket bore.  And a cam sprocket has no set screws meaning you'll have to machine spacers to "clamp" it in place like it is when the harmonic damper is bolted to the crank nose.

The cam sprocket is typically bolted to the camshaft with three or four bolts (depending on the engine it came from) and the center pilots on a boss on the front face of the camshaft.  That will also require some machining.

Really, I think it's easier to use machine sprockets which come in standard bore sizes, have set screws to lock them place, and are cheap.  It's only about $30 for a machine sprocket set with hardened teeth on the small one.
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Offline ChrisOlson

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Re: 180 volt 3.2 meter turbine
« Reply #49 on: March 04, 2012, 07:44:13 pm »
Just a few years ago, before your time in the discussions, 4' was small, 6~7' was big, and 10' was huge.

Yes, I suppose that's true.  But I see that the larger homebrew mills are not safe or practical too.  So the design has to change.  For instance, the "Otherpower 17", to my way of design, has a generator that's good for 2,500 watts continuous output strapped to a rotor than can easily develop 10 kW.  They build these things and burn 'em up.  So then they throw another in-hand turn in it to "beef it up" and it's still woefully inadequate.  And this design methodology has been "sold" to the unsuspecting newbie turbine builder as a "solid design".

When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator protected by a furling system that might work and might not, with the whole thing spinning on a frickin' trailer spindle that has an outer bearing with barely a 1" bore in the inner race.  About all I can say about that design is that it's damn good thing the people that designed it don't build bridges and tall buildings.
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Edit:
When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator protected by a furling system that might work and might not, with the whole thing spinning on a frickin' trailer spindle that has an outer bearing with barely a 1" bore in the inner race.

Oh yeah - and to top it off the whole contraption is held on the tower by a Jesus Nut with a cotter pin thru it.

Offline 97fishmt

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Re: 180 volt 3.2 meter turbine
« Reply #50 on: March 04, 2012, 08:21:32 pm »
Yea, I'm sure glad I didn't go that direction and keep scaling up a smaller turbine.
I also don't need the swept area like you and it just seems ridiculous to put up such
a large rotor and pray for the best. ???

Offline Watt

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Re: 180 volt 3.2 meter turbine
« Reply #51 on: March 04, 2012, 08:38:14 pm »
Just a few years ago, before your time in the discussions, 4' was small, 6~7' was big, and 10' was huge.

Yes, I suppose that's true.  But I see that the larger homebrew mills are not safe or practical too.  So the design has to change.  For instance, the "Otherpower 17", to my way of design, has a generator that's good for 2,500 watts continuous output strapped to a rotor than can easily develop 10 kW.  They build these things and burn 'em up.  So then they throw another in-hand turn in it to "beef it up" and it's still woefully inadequate.  And this design methodology has been "sold" to the unsuspecting newbie turbine builder as a "solid design".

When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator protected by a furling system that might work and might not, with the whole thing spinning on a frickin' trailer spindle that has an outer bearing with barely a 1" bore in the inner race.  About all I can say about that design is that it's damn good thing the people that designed it don't build bridges and tall buildings.
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Edit:
When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator protected by a furling system that might work and might not, with the whole thing spinning on a frickin' trailer spindle that has an outer bearing with barely a 1" bore in the inner race.

Oh yeah - and to top it off the whole contraption is held on the tower by a Jesus Nut with a cotter pin thru it.

Are you saying the rotor as it is designed for the otherpower 17' turbine lacks in power to drive the generator? 
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Offline rossw

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Re: 180 volt 3.2 meter turbine
« Reply #52 on: March 04, 2012, 08:58:25 pm »
Are you saying the rotor as it is designed for the otherpower 17' turbine lacks in power to drive the generator?

Quite the opposite.
I think he's saying
Quote from: ChrisOlson
has a generator that's good for 2,500 watts continuous output strapped to a rotor than can easily develop 10 kW.

Ie, the rotor (blades and hub) can easily develop 10kW, however the generator maxes out at 25% of that, so in a good blow the generator burns up rather than keeping the rotor under control.

Offline philb

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Re: 180 volt 3.2 meter turbine
« Reply #53 on: March 04, 2012, 09:00:50 pm »
Yea, I'm sure glad I didn't go that direction and keep scaling up a smaller turbine.
I also don't need the swept area like you and it just seems ridiculous to put up such
a large rotor and pray for the best. ???
I did go that way and burned up 6 stators before putting iron in them. That seemed to help keep the stator cool in turbulent winds.

The tapered roller bearings needed adjustment monthly on the seven I have built so far.

I still think the 'smaller' ones are good for a first build. It made the cogs turn. Windstuffnow had some good builds. He didn't try to make a 17 footer either. They don't scale up well IMHO.

Offline Watt

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Re: 180 volt 3.2 meter turbine
« Reply #54 on: March 04, 2012, 09:05:42 pm »
Just a few years ago, before your time in the discussions, 4' was small, 6~7' was big, and 10' was huge.

Yes, I suppose that's true.  But I see that the larger homebrew mills are not safe or practical too.  So the design has to change. For instance, the "Otherpower 17", to my way of design, has a generator that's good for 2,500 watts continuous output strapped to a rotor than can easily develop 10 kW.  They build these things and burn 'em up.  So then they throw another in-hand turn in it to "beef it up" and it's still woefully inadequate.  And this design methodology has been "sold" to the unsuspecting newbie turbine builder as a "solid design".

When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator protected by a furling system that might work and might not, with the whole thing spinning on a frickin' trailer spindle that has an outer bearing with barely a 1" bore in the inner race.  About all I can say about that design is that it's damn good thing the people that designed it don't build bridges and tall buildings.
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Chris

Edit:
When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator protected by a furling system that might work and might not, with the whole thing spinning on a frickin' trailer spindle that has an outer bearing with barely a 1" bore in the inner race.

Oh yeah - and to top it off the whole contraption is held on the tower by a Jesus Nut with a cotter pin thru it.

Ross, That is not what I understand by what is in red.

And, in yellow to be if Chris designs the rotor to drive that otherpower generator.   
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Offline ChrisOlson

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Re: 180 volt 3.2 meter turbine
« Reply #55 on: March 04, 2012, 09:22:48 pm »
Ross, That is not what I understand by what is in red.
And, in yellow to be if Chris designs the rotor to drive that otherpower generator.

No, Ross is right.  The generator in the Otherpower 17 (the latest version after the first one burned up) uses dual 14 in a 16/12 generator @ .3 ohm.  At 50 amps the thing is dissipating 750 watts, or just about 25% of the total power input to it, assuming a bank voltage of 50 volts.  That's hot.  Plug in a 750 watt heating plate, or coffee maker, or what have you, and lay your hand on it if you want to see just how hot that is.

I would in no way shape or form put that weak-kneed of a generator on a 17 foot rotor that is easily capable of putting 10 kW to the shaft at only 30 mph wind speed.  You have to understand with wind turbines that when I say "When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator" that the generator is what provides the braking torque for the rotor to keep it under control.  A grossly underpowered generator does not develop enough braking torque to control the the rotor.  So you have to rely on other methods, such as furling to reduce the swept area, or you'll burn it up.

Burnouts with the "otherpower 17" design are well documented by many folks who have built them and don't have thin mountain air to reduce the power thru the rotor.
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Offline Watt

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Re: 180 volt 3.2 meter turbine
« Reply #56 on: March 04, 2012, 09:27:05 pm »
Ross, That is not what I understand by what is in red.
And, in yellow to be if Chris designs the rotor to drive that otherpower generator.

No, Ross is right.  The generator in the Otherpower 17 (the latest version after the first one burned up) uses dual 14 in a 16/12 generator @ .3 ohm.  At 50 amps the thing is dissipating 750 watts, or just about 25% of the total power input to it, assuming a bank voltage of 50 volts.  That's hot.  Plug in a 750 watt heating plate, or coffee maker, or what have you, and lay your hand on it if you want to see just how hot that is.

I would in no way shape or form put that weak-kneed of a generator on a 17 foot rotor that is easily capable of putting 10 kW to the shaft at only 30 mph wind speed.  You have to understand with wind turbines that when I say "When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator" that the generator is what provides the braking torque for the rotor to keep it under control.  A grossly underpowered generator does not develop enough braking torque to control the the rotor.  So you have to rely on other methods, such as furling to reduce the swept area, or you'll burn it up.

Burnouts with the "otherpower 17" design are well documented by many folks who have built them and don't have thin mountain air to reduce the power thru the rotor.
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Chris

Thanks for the clarification Chris. 

Ross, no arguments, just needed clarification.  I have one of those flying and with my built in blunders, no comment otherwise. 
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Offline rossw

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Re: 180 volt 3.2 meter turbine
« Reply #57 on: March 04, 2012, 09:27:08 pm »
When I look at it, there is nothing "solid", or even remotely good, about a 17 foot turbine with a grossly under-powered generator

Ross, That is not what I understand by what is in red.

Well, we might have to wait for chris to answer - but the way I interpreted it was that the generator was "under-rated" (my term) for the job. I think "under-powered" may have just been a poor choice of words. As in, "it is not powerful enough".

In more "conventional" motor-generator sets, if you have a motor that is capable of 10kW and an alternator that is capable of 2.5kW, you can never burn out the motor. Even pulling maximum out of the generator, the motor is only lightly loaded.
The difference with that is that the motor is only delivering the power it needs to.

With a wind turbine, the wind *IS GOING TO TURN THE PROP*. If it's 100mph wind, that prop is going to be SCREAMING if you don't have something to keep it under control. And the only way to keep it under control is to have enough load... and if the prop WILL make 10kW and the generator can only suck out 2.5kW, you're going to burn up the generator - or if it somehow survives, your prop is still likely to overspeed.

Edit: Doh!  Was on the phone, hadn't hit enter. And now I see I'm two messages behind!

Offline ChrisOlson

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Re: 180 volt 3.2 meter turbine
« Reply #58 on: March 04, 2012, 09:38:09 pm »
Yes, in the commercial world of wind power a 17 foot machine will be typically rated at 6 kW output @ 12.5 m/s.  This allows for a generator efficiency of slightly better than 75% at full rated power.

In the case of the "otherpower 17" if you ever did get it to that output, continuous, you have a disaster on your hands.  Assuming you can drive your bank to 60 volts, you got 100 amps output with dual 14 gauge windings in the stator?  Even my grandson knows that's not going to work.
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Edit:  I would like to add that in the "real world" you'll probably have about 20 volts drop in the line getting the power from the gen to the battery.  Ideally, with this turbine you should have 40 volts drop.  So assume it's running at 100 volts at the generator @ 6 kW.  It's still putting out 60 amps.  That's way too much for dual 14 windings.

At 60 amps and .3 ohm it's dissipating almost 1,100 watts in the winding and you only got 3.6 kW output to your battery.  From the input shaft to the battery you're losing a whopping 4,160 watts.  This is why I don't consider much over a 12 foot wind turbine to be even remotely practical for battery charging.  You're better off with two smaller ones.

Offline Watt

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Re: 180 volt 3.2 meter turbine
« Reply #59 on: March 04, 2012, 10:12:20 pm »
Yes, in the commercial world of wind power a 17 foot machine will be typically rated at 6 kW output @ 12.5 m/s.  This allows for a generator efficiency of slightly better than 75% at full rated power.

In the case of the "otherpower 17" if you ever did get it to that output, continuous, you have a disaster on your hands.  Assuming you can drive your bank to 60 volts, you got 100 amps output with dual 14 gauge windings in the stator?  Even my grandson knows that's not going to work.
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Edit:  I would like to add that in the "real world" you'll probably have about 20 volts drop in the line getting the power from the gen to the battery.  Ideally, with this turbine you should have 40 volts drop.  So assume it's running at 100 volts at the generator @ 6 kW.  It's still putting out 60 amps.  That's way too much for dual 14 windings.

At 60 amps and .3 ohm it's dissipating almost 1,100 watts in the winding and you only got 3.6 kW output to your battery.  From the input shaft to the battery you're losing a whopping 4,160 watts.  This is why I don't consider much over a 12 foot wind turbine to be even remotely practical for battery charging.  You're better off with two smaller ones.

On page 268 of the " Homebrew Wind Power " book it does say it's a 3000 or more continuous watt turbine and peaks of double or more are possible from it.  I only wish the wind blew hard enough around here for long enough to burn that thing to the ground.  Then, I'd have a reason to put up one of yours. 

In reality, for what it's used for and where it is placed, it does fine.  I did make a few changes to it, bearings for one as well as magnet rotor diameter and 3 in hand 14awg copper.  The copper was in fact a recommendation I got from fieldline members. 

So, even though those plans were published, I have to respect that the Dans do admit and update as problems arise.

Edit:  I said even though those plans were published, what I mean by that is:  Because the plans were published, and because the Dans have included at least one acknowledged weakness, I respect the Dans for their updates. 

I should also make a point to thank you too as well Chris for helping the rest of us that have not been fortunate enough to experiment and prove different ideas as you have.  So, Thank you.
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