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Too much excitement this morning
By DanB, Section Wind Posted on Fri Jun 6th, 2008 at 02:17:59 PM MST
Run away 17' wind turbine

Interesting morning I had. I woke up to lots of noise from my 17' wind turbine (blade flutter). DanF called me on the radio and asked if I needed to borrow a shot gun, he could hear it from his house and knew exactly what was going on. (of course he's kidding, we don't normally shut down wind turbines with a shot gun)
The line down the tower for the 17' machine is quite old, I should've replaced it years ago. It's on a turbulent site so it does twist up quite a bit (usually I untwist it every 3 months or so). It also didn't have very good strain relief at the tower top. A couple months ago the line broke right at the top of the tower - and fell down the tower. Fortunately it shorted itself out and it's just been sitting up there for a while. I've not lowered it yet to fix it for the following reasons:

I don't really need the power from that machine-
I lower it with a truck and there's been snow back there (bad traction)
we've been busy
I've been lazy about it
For some reason last night (while sleeping) it 'unshorted' itself and took off in fairly high winds! I let it go for about an hour after I woke up to watch it, thinking maybe I'd witness a good crash. It was interesting. The machine was furling still (which is good) but definitely furling late and the load on the tower was quite a lot more than normal. It actually bent the tower above the top guy wires a few degrees.
After consuming a reasonable qty of coffee I brought my truck into position, connected it to the gin pole and let the back guy wires loose. Then I ran around to the other end and tried to pull the tower over enough to overcome the weight of the gin pole - fairly impossible with any wind blowing though due to thrust against the blades, so I had to wait for a calm period. I pulled it over - ran back to the truck just in time to see the wind blow the tower back up into position. We (the tower and I) went through this three times before I finally was able to lower it. In the end it all came out fine but it sure was scary for a bit!
It was encouraging to see it hold together at such extreme rpm anyhow - and it was nice to see that it still would furl under these conditions.
The tower is pretty junky and not really up to a 17' turbine. I'll likely not put this machine back up on that tower. I'll either replace the tower with something more rigid, or test a smaller turbine on it.

Too much excitement this morning | 14 comments (14 topical, 0 editorial)

Re: Too much excitement this morning (3.00 / 0) (#1)
by Jimmy D on Fri Jun 6th, 2008 at 08:30:46 AM MST
(User Info)

Dan
If you had some help you didn't mention I apologize. Otherwise you need your butt kicked for doing this alone. Even a youngster in the safe zone could have run for help if you were some how pinched or trapped.
I enjoy your work and posts to much to loose you this way.
Jim

Re: Too much excitement this morning (3.00 / 0) (#2)
by DanB (danb@*no spam*otherpower.com) on Fri Jun 6th, 2008 at 08:56:09 AM MST
(User Info) http://www.otherpower.com/

DanF was here but I didn't ask for help, I felt more comfortable doing it alone to be honest.

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#3)
by wdyasq on Fri Jun 6th, 2008 at 08:58:45 AM MST
(User Info)

AND, he had his shotgun to dispatch you if you got into something you couldn't get out of ....

Ron
Adventure is just bad planning." -- Roald Amundsen
[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#4)
by Dave B on Fri Jun 6th, 2008 at 10:04:39 AM MST
(User Info) http://www.madbbs.com/users/bruggelog

Dan,
Thanks for sharing your bit of excitement. I've been there and had the crash besides (over powered alternator and late furling) Murphy's law in action with the electrical shorting switch as a brake, it's only good if there is no open from the switch through the coils AND your alternator is powerful enough to hold back the blades. Score one for the mechanical brake, I have one and will never put a machine up without one. Thanks for the story, I hope Murphy doesn't strike a second time with your 20' machine. Dave B.

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#9)
by elvin1949 (elvin1949@yahoo.com) on Sat Jun 7th, 2008 at 01:49:34 AM MST
(User Info)

OK
Someone had to hold the shotgun. Sorry couldn't resist.
Glad you got it down with no major damage to person's or property.
later
Elvin

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#11)
by TomW on Sun Jun 8th, 2008 at 05:42:39 AM MST
(User Info)

Elvin;

HaHa, yep.

Nothing that cannot be solved with the judicious application of firepower.

Tom

"Education consists mainly of what we have unlearned."--Mark Twain
[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#13)
by elvin1949 (elvin1949@yahoo.com) on Sun Jun 8th, 2008 at 10:46:43 PM MST
(User Info)

Tomw
Thought you would see the humor.
Have fun
later
Elvin

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#5)
by jmk on Fri Jun 6th, 2008 at 11:38:00 AM MST
(User Info)

I always raise and lower my tower by myself. I know what it's like to have the tower teeter back up, but I can't imagine doing it while the turbine is spinning unloaded in wind. I have an extra cable hooked to a hand winch so I can tilt it past the teeter point of the gin pole,(it weighs 600 lbs so I cant just pull on the cables). I also know where to have the front wheels of the truck so when I am cranking in on the tower and rocking past the balance point the truck will catch the tower. I guess with the turbine running that balance point might not work till the wind dies down. Doing it so many times now I prefer to have no one around incase something does go wrong. I am only in danger while cranking the wench. After that I am 180' away in my van because I use a double block on the gin pole and a double block at the footing. The blocks eat up a lot of cable while lowering, and the tower is down about the time I get up to it. It took a lot of back and fourth to figure it out, and it took a couple more times before I marked where to have the van to start with. It sounds like you made it okay. That could have gotten real hairy in the wind. I think it's a good idea to have someone there watching while out of the way. I have raised mine and then unsorted it at the tower while forgetting that I had the batteries unplugged at the other end. I got half way back to see it furling while spinning fast making helicopter noises, so I can picture what you went through, and I bet it was scary!
jmk

Re: Too much excitement this morning (3.00 / 0) (#6)
by Ungrounded Lightning Rod on Fri Jun 6th, 2008 at 01:33:50 PM MST
(User Info)

Try this next time: Get a pulley riding the uppermost guy wire on the side opposing your gin pole and run a rope from it to a pulley at the tower base and from there through another pulley at the base to where you're truckin' it down.

Pulling on the rope should first run the pulley up the guy wire and then pull at near right angles near the middle of it. This gives INCREDIBLE leverage - at least until the guy wire is no longer very straight - by which angle the tower should be on its way down, hurricane or no.

You can use a similar trick to pull a stuck car out of a hole - an inch at a time - with one finger pushing on the middle of a tow cable.

Just hanging a goodly weight as high as you can reach on one of the opposing guy wires will do a similar thing, though with much less strength.

Re: Too much excitement this morning (3.00 / 0) (#7)
by JW on Fri Jun 6th, 2008 at 06:28:27 PM MST
(User Info)

Wow,

I had not realized, that I have been still logged in, from the other day.

I was planning to go out on the boat this weekend and if the wind dies down some, may still do that.

With, 20mph gusts, thru-out the day(today) makes the seas very choppy. I would use a 'redundant band-brake' on any windturbine, that I set up off-of the coast of the ocean in my area.

Were now going into hurricane season, on the southern east coast down here in Miami FL. If I actually had a wind turbine set-up on one of the barrier island/keys down here, I would be sure to build a vertical drum band brake, of-off the rear-rotor on any (dual-rotor)machine that I would raise.

In this way, as I made it to the location(by boat) of such a wind turbine tower(providing that I was not there at the time), I would have a positive way to stop rotation of the mill, before I set the tower down.

After the hurricane warning passed, go back out there and raise it again.

Ive been pondering the ideal of starting a 'Wind-Power Club' in my area. Just thinking out loud.

JW

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#8)
by Ungrounded Lightning Rod on Fri Jun 6th, 2008 at 06:59:45 PM MST
(User Info)

Make that: "Get a pulley riding the uppermost guy wire on the side opposing your gin pole and run a rope from it through another pulley at the base to where you're truckin' it down."

I somehow managed to type the pulley-at-the-tower-base in there twice. B-(

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#10)
by windy on Sat Jun 7th, 2008 at 09:11:42 PM MST
(User Info)

DanB
Glad to hear that it didn't disintegrate. What do you estimate the runaway RPM was? I'm just curious. I have seen my 10 foot diameter blade go well over 600 RPM, fully furled, and it never gives me any problems.

Re: Too much excitement this morning (3.00 / 0) (#12)
by DanB (danb@*no spam*otherpower.com) on Sun Jun 8th, 2008 at 07:37:25 AM MST
(User Info) http://www.otherpower.com/

My best guess is around 900 rpm.

[ Parent ]

Re: Too much excitement this morning (3.00 / 0) (#14)
by mbeland on Mon Jun 9th, 2008 at 06:50:06 AM MST
(User Info)

DanB

Can you remind us what size pipe or tubing your tower and tower stubb were made of so no one makes it smaller? Did it bend above the stubb or below?

Martin
Eau, soleil, le vent
[ Parent ]

Too much excitement this morning | 14 comments (14 topical, 0 editorial)

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