something to think about….
makes you wonder how many other units had to trip offline when this happened
http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=29249089
something to think about….
makes you wonder how many other units had to trip offline when this happened
http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=29249089
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Replies
Back in the early 1980s, consulted a little on the big multi-megawatt unit in Goldendale, WA.
Feathering controls failed once and a runaway, this puppy had a 4340M steel shaft IIRC 14" dia tempered to above 250 ksi, twisted that puppy right in half.
yeah, I read somewhere that the brakes are always on...I have seen pictures at some wind sites that show extreme flexing in high wind and this one just looks like it flexed too much.still wonder how much plant output went out when this happened.
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un believable!!!!
no doubt, wouldn't want to be the crew that install the next one while its neighbors are running.
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make you think!!!
maddog,
you can see the problems as they developed over speed burned out the bearings and yet the wind speed forced it to turn when it couldn't and the result was the blow up you see..
There is a feathering capability that clearly failed
well wouldn't that be a problem for large "farms" !if one fails for that reason they ALL could fail.
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maddog3
do all bearings fail at the same time? Nah! a small percentage of bearings fail early on and most run a very long time.. I can't remember when the last time I saw a catistrophic engine failure can you? I mean where a new car's engine blows up with smoke and steam coming out the top and parts falling out the bottom..
bearings ? I didn't think it was a bearing, it may have been just a bad blade
I assumed a blade hit the tower so I tried clicking through the video and you can see one blade separating from the hub at 12 o'clock after it whacked the tower while the other two are still intact.. if only brieflyso I wondered if high winds would cause all the units to suffer similar damage
and if the sudden loss of output by just one or more would cause a service interruption or a blackout.
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maddog3
Don't you see the momentary pauses in the video? At irreggular intervals but definate slowdowns. Typical of a bearing going bad.. sieze release, sieze again release again.
Momentary pauses?? That's just the effect of the camera film rate.
For a bearing failure the hub sure seemed to be spinning just fine after the blades seperated.
Tom
Caused me to go back and relook at the video, and It's hard but it does appear that there is fore and aft blade deflection. I'll admit I don't know for sure.. and I wouldn't want to take a position on it without a better video which I doubt I'll see..
I do know that there was a failure.. first the blades should have feathered/ feathering at that sort of wind speed.. which in my unexpert eyes supports overspeeding. Leading to bearing failure, causing the pauses etc.. once the load is off the bearings the hub would be free to continue to turn but watching it carefully it's not appearing to freewheel it definately looks like it's slowing.
We aren't likely to know will we? experts will check it out I'm sure but the first failure was lack of feathering..
They are definately not meant to run in those winds. I guess it was out of control and the camera guy figured something's gotta happen. And it did.
They have installed over 1,500 wind turbines between Sweetwater and Snyder Texas... the 1-3 megawatt, 250ft. tall Towers.
I understand those big units shut down when a constant wind speed exceeds 26 mph. The blades are up-wind versions like the one in the video, so when they begin to flex or become out of balance due to ice, they can have a tower/blade strike...
The downwind units lets the blades run behind the support tower. That design is a bit noisy because of the wind-shadow as it splits and goes around the tower before it pushes the blades.
Bill
My friend who installs windmills for Solar Village Institute showed me a new system where the blades are made from the same rubberized material they make heavy duty trash cans from and they sit down wind from the post. In a hurricane force wind they just deflect and "feather" themselves and even if they fold out straight they won't hit the column or damage the machine.
I'm building a model of the Quiet Revolution helical vane vertical axis windmill from England with my 10 year old daughter for a school project. That is an elegant design. http://www.quietrevolution.com
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"You cannot work hard enough to make up for a sloppy estimate."
"Beautiful" I like that oneand I hope your daughter enjoys great success with her project ......
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Here's a picture as we were putting the final touches on it out on the front porch last night. She did a great presentation in class this morning and the construction was tough enough that when the class bully gave it a spin it didn't explode. (I saw what he did to her truss tower project and built it extra tough with him in mind and the first time she brought it into the class room and he made a bee line for it I stepped in front of him and gave him a major hairy eyeball.) We'v gotten really pumped about the whole thing and are going to do a prototype number three this weekend with a better bearing tube and wider spreader bars to get better leverage. Now the teacher wants us to build a bicycle generator and hook it up to switchable incandescent, CFL, and LED bulbs to demonstrate energy efficient lighting.------------------
"You cannot work hard enough to make up for a sloppy estimate."
Neat project, keep us updated. Is the turbine actually designed to produce electricity?
And I see you've got the energy efficient automatic mowers too.
jt8
"A single rose can be my garden...a single friend, my world." --Leo Buscaglia
Edited 3/7/2008 3:54 pm by JohnT8
No. it is just designed to demonstrate the aerodynamic properties of the helical vanes on the vertical axis configuration. The lawn mowers are great, St. Croix "hair sheep".------------------
"You cannot work hard enough to make up for a sloppy estimate."
that really turned out nice Nerd, perhaps you could provide a walkthrough, with pictures of course, on the next one, since you and your pretty assistant do very nice work.
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Wow ! I can't help but reflect on my 1932 model Aermotor Windmill, down on the farm, here in South West Georgia. I took it down in 1974, and finally put it back up (moved to another location) in 2004.
Aermotor has been manufacturing farm windmills since 1888. The technology is pretty amazing. There's an oil-bath crank-case on those buggers, and the reduction drive is very well engineered. My 8 foot mill, rotating in a mild wind, creates a stroke of about 8 inches, but with enough power to pump 200 gallons of water an hour.
The pertinent fact here is that the windmill has a furling mechanism that actually turns the mill out of the wind in a high speed wind - effectively preventing the machine from destroying itself. Pretty good thinking for 1888 technology.
Greg
I haven't seen a well driven pump around here for years
how do you use the water ?.
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I have 25 acres of pecan trees, all under a drip irrigation system. But the windmill is on the other side of the paved road. I have 6 trees close to the windmill that don't have water run to them. I plan to water those trees from the windmill pump.
Someday, I may have a pond dug, just 1 1/4 acre or so. A windmill is a wonderful thing to have by a pond; no electricity, no fuel, just the constant stroke of the windmill.
I'll try to post a photo - the tower is 54 feet tall, and in our flat land, you can see for miles.
Greg
pictures would be great, I'll bet it's quite the view perched on top of that.
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Wow ! I can't help but reflect on my 1932 model Aermotor Windmill, down on the farm, here in South West Georgia. I took it down in 1974, and finally put it back up (moved to another location) in 2004.
If you took pics along the way, start a thread in the photo gallery section. would be neat to see.
We used to have those mills scattered all over the place, but now they're pretty rare.
jt8
"Worry never robs tomorrow of its sorrow, it only saps today of its joy" --Leo F. Buscaglia
Edited 3/7/2008 11:50 am by JohnT8
Okay - a challenge ! I didn't have a digital camera then, so I'll have to scan the prints and then figure out how this photo attachment deal works here. I'm up for it - I have the gear, just no experience.
Watch for it !
I was 17 when I took it down. I put it back up at age 48. I still climb it at 51.
Greg
Greg,
I had a 60+year old uncle that had a steel tower he climbed. He fell to his death....
They found that as he was more than half way up, he disturbed a nest of wasps by either putting his hand on the nest or from the vibration of just climbing and lost his grip.
I've come to see that 50 feet looking up is way shorter than when you're 50 feet in the air and looking down!!!
Be careful on that tower,
Bill
FYI - When driving in NY an PA this summer, I noticed small windmills in the middle of many fields of grape vines. I was guessing... making electricity or pumping water. When we finally went to a vineyard in PA, they explained: When it gets cold, we turn on the windmill and it blows the frost into the neighbors yard! Neat trick!You get out of life what you put into it......minus taxes.
Marv
>>Pretty good thinking for 1888 technology.<<
Actually it does not surprise me.
"When men were iron and ships were wood."
1888 was not that far into the steam age for ships.
I think the engineers (at least the ones with gray hair) had a pretty good grip on wind as a power source and what needed to be done to protect equipment when there was too much of it.
JimNever underestimate the value of a sharp pencil or good light.
that was insane. reminded me of that episode of House in antactica, started just then same....
hmmmm, your post perplexs me
I didn't see that one..
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same video is on youtube.. folks there said the brake on the windmill failed and the truck in the picture is workers who were working on fixing it.
Apparently it was spinning at the uncontrolled speed for a few hours prior to it suddenly breaking up.
working on it !man that's just crazy.
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