But the generator is and always has been stalled during wind storms. Nothing's changed, in that regard.
This is why we're mystified. ++++++++++++++++++++++++++++++++ <insert witty tagline here> ----- Original Message ----- From: "Patrick Shoemaker" <shoemak...@vectordatasystems.com> To: "WISPA General List" <wireless@wispa.org> Sent: Wednesday, May 27, 2009 2:55 PM Subject: Re: [WISPA] (topic change) sort of tower failure... > Ah. Was the generator shaft spinning freely during the last two > windstorms? A stalled (or nearly stalled ~ 15 RPM) rotor will present a > much higher wind load to the tower than a freewheeling one will... > > Patrick Shoemaker > Vector Data Systems LLC > shoemak...@vectordatasystems.com > office: (301) 358-1690 x36 > http://www.vectordatasystems.com > > > rea...@muddyfrogwater.us wrote: >> No, nothing like that. The generator had purely electrical failure, and >> was stuck in the "brake" mode, where the shaft only spins at perhaps 15 >> rpm, >> no matter the wind. >> >> I'd like to think I'm thorough, and yet I have found no reason for the >> tower >> failure. We're putting it back up about 60% stronger. Well, when it >> gets back, that is. >> >> >> >> >> >> >> ++++++++++++++++++++++++++++++++ >> <insert witty tagline here> >> >> ----- Original Message ----- >> From: "Patrick Shoemaker" <shoemak...@vectordatasystems.com> >> To: "WISPA General List" <wireless@wispa.org> >> Sent: Wednesday, May 27, 2009 1:51 PM >> Subject: Re: [WISPA] (topic change) sort of tower failure... >> >> >>> Was the generator shaft seized? Variable pitch blades locked at the >>> shallowest position? >>> >>> >>> Patrick Shoemaker >>> Vector Data Systems LLC >>> shoemak...@vectordatasystems.com >>> office: (301) 358-1690 x36 >>> http://www.vectordatasystems.com >>> >>> >>> rea...@muddyfrogwater.us wrote: >>>> Ok, so, two weeks ago, after having stood for 4.5 years, through 2, and >>>> I >>>> mean TWO "century" wind storms, my generator tower failed on a very >>>> normal >>>> normal windy spring day. >>>> >>>> We took it the rest of the way down, cut it apart, looking for the >>>> cause >>>> of >>>> failure. >>>> >>>> And found none. No rust, no breaks, no corrosion, nothing. >>>> >>>> And found while it was down, that the generator windings and >>>> electronics >>>> had >>>> burnt themselves up, as well. >>>> >>>> A real head scratcher. All the "obvious" stuff ain't there. >>>> >>>> All we can think of is that there was some very localized freak >>>> conditions >>>> that did what the storm a year and a half ago could not do. The >>>> storm >>>> then was so strong that about 1/3 of all homes suffered significant >>>> roof >>>> damage. Fields migrated across roads. RV's tipped over. parked >>>> Semis >>>> tipped over. metal buildings exploded. Wind velocities at the normal >>>> stations set records. individual weather stations recorded high >>>> hurricane >>>> velocities. >>>> >>>> But our tower didn't bend or even show damage. >>>> >>>> But two weeks ago, where we had predicted "gusts" to 35 or 40 mph, >>>> caused >>>> it >>>> to fold. We had changed the blades on it a couple weeks before, on >>>> the >>>> advice of the maker of the generator. They insisted that wind loading >>>> was >>>> within 1% of the original. >>>> >>>> So, we're re engineering it and back up it goes when the generator gets >>>> back >>>> from the maker (who is rebuilding it under warranty). >>>> >>>> I love a mystery. NOT. >>>> >>>> >>>> >>>> >>>> >>>> >>>> ++++++++++++++++++++++++++++++++ >>>> <insert witty tagline here> >>>> >>>> >>>> >>>> >>>> -------------------------------------------------------------------------------- >>>> WISPA Wants You! Join today! >>>> http://signup.wispa.org/ >>>> -------------------------------------------------------------------------------- >>>> >>>> WISPA Wireless List: wireless@wispa.org >>>> >>>> Subscribe/Unsubscribe: >>>> http://lists.wispa.org/mailman/listinfo/wireless >>>> >>>> Archives: http://lists.wispa.org/pipermail/wireless/ >>> >>> -------------------------------------------------------------------------------- >>> WISPA Wants You! 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