Re: [WISPA] (topic change) sort of tower failure...
But the generator is and always has been stalled during wind storms. Nothing's changed, in that regard. This is why we're mystified. - Original Message - From: "Patrick Shoemaker" To: "WISPA General List" 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. >> >> >> >> >> >> >> ++++++++++++++++ >> >> >> - Original Message - >> From: "Patrick Shoemaker" >> To: "WISPA General List" >> 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. >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> WISPA Wants You! Join today! >>>> http://signup.wispa.org/ >>>> >>>> >>>> WISPA Wireless List: wireless@wispa.org >>>> >>>> Subscribe/Unsubs
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. > > > > > > > > > > - Original Message - > From: "Patrick Shoemaker" > To: "WISPA General List" > 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. >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> 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! 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! 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! 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/
Re: [WISPA] (topic change) sort of tower failure...
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. - Original Message - From: "Patrick Shoemaker" To: "WISPA General List" 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. >> >> >> >> >> >> >> >> >> >> >> >> >> >> 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! 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! 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/
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. > > > > > > > > > > > > > > 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! 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] (topic change) sort of tower failure...
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. 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/
