[TowerTalk] AN tower
Roger (K8RI) on TT
K8RI-on-TowerTalk at tm.net
Sun Jun 21 15:06:55 EDT 2015
I saw this back when I had a working headset on this computer. The
"tour" with no sound wasn't very informative, but I have a new set on
order which should be here Tuesday or Wednesday. So many things are
nicer with sound, like videos, some tutorials, and movies. <:-))
BTW, most locals say the generators are almost silent...except for a guy
who complains about the rumble strips on the highway keeping him awake.
Those rumble strips are over 2 miles away from his house <LOL>
You can stand up close and just hear a "swishing" sound.
73
Roger (K8RI)
On 6/21/2015 12:55 PM, Gary - AB9M wrote:
> 6 minutes on how the wind turbine tower is built
> https://www.youtube.com/embed/84BeVq2Jm88?feature=player_detailpage
>
>
> 73 & DX,
>
> Gary - AB9M
> -----Original Message----- From: Gary - AB9M
> Sent: Sunday, June 21, 2015 11:33 AM
> To: Roger (K8RI) on TT ; TT TowerTalk
> Subject: Re: [TowerTalk] AN tower
>
> See https://www.youtube.com/watch?v=nL0EjOmuPwY for info from a local
> wind
> farm
>
> 73 & DX,
>
> Gary - AB9M
> -----Original Message----- From: Roger (K8RI) on TT
> Sent: Sunday, June 21, 2015 11:08 AM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] AN tower
>
> We have a lot of wind generators in the area (County) where my farm is
> located. Of course those are the monster, commercial generators with
> the entire farm generating many megawatts. (Look up Gratiot county wind
> farm)
> It covers a large area and another two wind farms to the S and SW have
> been added. Studies have shown the wind speed is ideal most of the time
> with power that is price competitive with conventionally generated power.
> Those are mounted on a single pole that is massive.
>
> A windmill tower on steroids, which this appears to have been, does not
> scale well from the 8 to 10 or 12' windmills of old to the large 3 blade
> props large enough to generate useful power in average winds. Most are
> variable pitch so they keep the RPM to a level limiting that gyroscopic
> action, or even shut them down in high winds. A "windmilling" prop has
> far more wind resistance than one that has stopped. An airplane will
> glide much farther with a stopped prop than one that is windmilling. I
> wonder what the wind resistance, or equivalent area of one of those big
> props would be.
>
> I've seen quite a few home systems that appeared to be on 45G or even
> 25G, guyed towers. It "appeared" to take quite a breeze to get the
> smaller blades turning. They "appeared" to be turning the equivalent of
> 2 or 3 car alternators. What they were really turning? I don't know.
>
> They told over at the farm that some of the prop tips can reach as high
> as 400 feet
>
> I wonder if this generator had a variable speed prop with speed control.
> A prop large enough to give useful power in average winds must be quite
> massive with the associated gyroscopic action.
>
> 73
>
> Roger (K8RI)
>
>
> On 6/21/2015 9:43 AM, Patrick Greenlee wrote:
>> A caveat regarding wind generators on towers. A good friend had a
>> 100 ft tower with wind generator on top. Unfortunately it was not
>> properly engineered for a wind generator although it was sold
>> expressly for that purpose as a package deal. In just a few years
>> the tower failed and crashed to the ground destroying the generator
>> and mangling the tower components.
>>
>> The tower was constructed of seamless steel tubing with 1/4 walls and
>> 4 inch ID in 20 ft lengths with welded on flanges for bolting
>> together. The three legs are on 14 ft centers at the ground, a fairly
>> substantial tower. Each leg sat on an 18 inch diameter 7 ft deep
>> concrete pier. So why did it fail?
>>
>> When spun up by the wind the generator makes a considerable
>> gyroscope. When the wind changes direction without slowing
>> considerably first the gyroscope translates a change in azimuth to a
>> force trying to tilt the generator up or down (aim the generator's
>> axis of rotation out of the horizontal.) This gyroscopic action was
>> not properly allowed for and eventually led to the towers dramatic
>> catastrophic failure.
>>
>> Towers well designed for supporting antennas may not be built such
>> that they will survive the gyroscopic force translations. Sufficient
>> materials were salvaged from this collapsed tower to reconstitute the
>> bottom 40 feet. I tilted that 40 ft recreation over (two hinged
>> legs) and dismantled it for transit to my QTH and have refurbed it.
>> It may be seen on my QRZ page along with the three foundations for
>> its legs. The guy on the ladder is my good friend John who is mech
>> eng with 35 years hands on experience. He sanity checks my wild
>> ideas as well as visiting me for 10 days each year to help with
>> projects.
>>
>> Executive summary: Be careful just sticking a wind generator on a
>> tower designed for antennas. You might be in for an exciting surprise.
>>
>> Patrick NJ5G
>>
>>
>>
>> On 6/19/2015 7:30 PM, David Gilbert wrote:
>>>
>>> Well, in my case, I had to allow for some ridiculous wind issues
>>> here at my QTH and I wanted to make sure that whatever tower I put
>>> up would handle any large antenna (or wind generator) I might one
>>> day decide to install on it, since I certainly was only going to
>>> have one tower ... ever. I live on an easterly hillside near the
>>> south end of a mountain range where the dominant wind direction is
>>> from the southwest. The winds that get blocked by the south end of
>>> the mountain range recover in the form of swirlers that roar down
>>> the hillside and across my lot like a freight train. Spring
>>> thermals bring wind gusts every three to five minutes that often
>>> reach 70 to 80 mph, and I've seen days where 90 mph is not
>>> uncommon. The strongest I've recorded was greater than 100 mph, and
>>> that on a clear day.
>>>
>>> So I bought the strongest tower I could reasonably afford, although
>>> the Trylon might be the better value in terms of cost versus
>>> utility. To each his own.
>>>
>>> I do agree that the foundation seems to be overkill, though, and
>>> mine took 20 cubic yards of concrete. That's roughly 40 tons worth
>>> planted six feet in the ground, and if the tower was five times
>>> stronger than it is now I bet it would still fail before the
>>> foundation budged.
>>>
>>> The rebar cage design looked odd to me as well, but I didn't have
>>> any problem at all building it --- as the pictures on my web site show.
>>>
>>> Shipping (from Pennsylvania at the time) was also expensive. I
>>> bought mine in 2008 and the freight cost to southern Arizona was
>>> almost $1200, and it would probably be even more now.
>>>
>>> No doubt about it ... my tower and antennas have far and away been
>>> the most expensive aspects of my ham radio addiction.
>>>
>>> 73,
>>> Dave AB7E
>>>
>>>
>>>
>>>
>>> On 6/19/2015 10:29 AM, K7LXC--- via TowerTalk wrote:
>>>> Howdy, TowerTalkians --
>>>> I've installed dozens of towers at amateur and commercial
>>>> sites over
>>>> the years and I have found the AN towers to be battleship stout
>>>> (which in
>>>> many cases is not necessary for a ham installation) but expensive
>>>> to buy and
>>>> install.
>>>> One of my major complaints is that the base design is WAY
>>>> overbuilt
>>>> compared to all the other towers I've installed. The last one
>>>> specified
>>>> approximately 3 times the amount of concrete than for similar
>>>> towers from other
>>>> manufacturers. To me it's a pure waste of time and money for the
>>>> unneeded
>>>> additional concrete.
>>>> Also the rebar cage is overly complicated in its design.
>>>> I've built
>>>> many rebar cages but I had to hire a concrete contractor to be able
>>>> to build
>>>> it per their spec. Even the concrete contractor was scratching his
>>>> head
>>>> over the design.
>>>> To me, this is another instance of an engineer working in an
>>>> air
>>>> conditioned office who designs it but never has to be out in the
>>>> field to
>>>> install one. (They're not the only manufacturer to do this.)
>>>> For a similar tower height and capacity, anyone installing a
>>>> Trylon
>>>> Titan tower would save up to $3000+ by buying it rather than the
>>>> AN. Just
>>>> offering a money saving option.
>>>> Yes, I sell Trylon towers but that's because I've found them
>>>> to be the
>>>> best value in a self-supporting tower around and lots of people are
>>>> interested in that.
>>>> Cheers,
>>>> Steve K7LXC
>>>> TOWER TECH -
>>>> Professional tower services for amateurs
>>>> Cell: 206-890-4188
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>
>>>
>>> _______________________________________________
>>>
>>>
>>>
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>>
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>>
>>
>>
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>
--
73
Roger (K8RI)
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