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makourain

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Joined: 19/04/2006
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Posts: 111

Posted: 12:37am 31 May 2006

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if windmills go spin too fast they spit the dumby and dont like it, well ur equipment doesnt anyway.
so i was thinking that there could be a way to slow it down if it gets too fast, by way of a centrifugal break.
the wind spins the mill around, and the mill has attached to it a small pole with a spring on it to keep it from touching the outside of a ring of rubber. the pole would have a rubber foot on the end of it so that when its spinning fast enough to make the foot touch the rubber ring it will slow it down.

another idea is to use a whole bunch of step down transformers that would engage depending on the wind speed. an annenometer would detect wind speed and send a control mechanism the instructions to choose the best transformer for the speed. this way u can still keep using the mill even at high speed and only have the amps going up instead of the volts.

just brainstorming.

RossW
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Joined: 25/02/2006
Location: Australia
Posts: 495

Posted: 03:48am 31 May 2006

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makourain said if windmills go spin too fast they spit the dumby and dont like it, well ur equipment doesnt anyway.
[/quote]

More like.... "they fly apart and could maim or kill you"

[quote]
so i was thinking that there could be a way to slow it down if it gets too fast, by way of a centrifugal break.
the wind spins the mill around, and the mill has attached to it a small pole with a spring on it to keep it from touching the outside of a ring of rubber. the pole would have a rubber foot on the end of it so that when its spinning fast enough to make the foot touch the rubber ring it will slow it down.
[/quote]

A few problems.
1. because the thing would have to slide in and out, it would affect the balance of the whole turbine.
2. its going to get wasps, dirt, grime etc build up on it and when you really need it to operate, it won't (see "murphys law")
3. rubber won't wear very well
4. not withstanding (3), rubber would "catch", and I hate to think what the force would be up close to the hub!

Perhaps a better solution might be a centrifugal CLUTCH off a minibike, or perhaps a chainsaw. With the outer disk mounted firmly to the casing of the generator, or otherwise attached to the mast - when the clutch starts to engage it'd retard the prop.

[quote]
another idea is to use a whole bunch of step down transformers that would engage depending on the wind speed. an annenometer would detect wind speed and send a control mechanism the instructions to choose the best transformer for the speed. this way u can still keep using the mill even at high speed and only have the amps going up instead of the volts.

just brainstorming.

A stack of transformers will be costly and heavy, and cumbersome to switch. An autotransformer (or variac) might be more practical.

Many years ago, when I was an apprentice, we had a large 3-phase "AVR" - the mains to our test range were under-sized (but couldn't be changed) and we used a lot of power - so the 3 phase mains came in to a cabinet with three large variacs (variable transformers) mounted on their side, with a large fibreglass rod between them, and a motor on the end of that. The output voltage went through a comparator which drove the motor clockwise or anticlockwise to drive the variac to the "right" point. Quick, infinitely variable, simple and reasonably reliable.

Of course, nowdays, MPPT supplies achieve all this without any moving parts, and with (probably) higher efficiency.

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5019

Posted: 09:35am 01 Jun 2006

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I'm a big fan of the furling tail. They just seam to work so well.

This photo shows a windmill in the furled condition. The blades appear stationary as it was a fast shutter speed on the camera, but you can see the tail rope and even the drop wire are blown back. The turbine is turned out of the wind, reducing its frontal area to the wind, and not over speeding.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

makourain

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Joined: 19/04/2006
Location:
Posts: 111

Posted: 10:48pm 01 Jun 2006

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how exactly does this work?

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