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RE: [s-w-h] Chinese Inverters - my latest failure

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  • Robert Bruninga
    I have not been following this thread at all, but why not use solar Microinverters? Use a noiminal 48v turbine and feed as many 24v solar microinverters in
    Message 1 of 11 , Mar 8, 2013
      I have not been following this thread at all, but why not use solar
      Microinverters?

      Use a noiminal 48v turbine and feed as many 24v solar microinverters in
      series parallel are needed to handle the power? I see 500W microinverters
      and they operate with a nominal 30v input (peak of 55v) So each pair in
      series will give 1 kW and accept an input from below 48v up to 110v DC
      (assuming their inputs are isolated).

      I am sure this has been discussed before, if so, don't shoot me. Just a
      thought.
      Bob, WB4aPR

      -----Original Message-----
      From: small-wind-home@yahoogroups.com
      [mailto:small-wind-home@yahoogroups.com] On Behalf Of Doug
      Sent: Monday, February 11, 2013 12:11 PM
      To: small-wind-home@yahoogroups.com
      Subject: [s-w-h] Chinese Inverters - my latest failure

      Howdy all:
      The regulars here may remember I had finally found a grid-tie inverter
      made for wind turbines, made in USA, that rejected overvoltage rather than
      being sizzled to a cinder. It was looking like we would finally be able
      to offer a reloiable grid-tie home wind energy package.

      As it turned out, the U.S. company producing these over-voltage-proof
      inverters went out-of-business right after I bought one, taken over by
      Bergey who, according to Mike, had decided not to sell the inverters to
      "competitors". (My thought was if I were buying these I could be thought
      of as a "customer" rather than a "competitor". One thing I've learned in
      business is you don't really know what products you make, that people
      want, until the orders start coming in!)

      Anyway these U.S.-made 6 kW inverters are really overkill for my little 2
      kW turbine, so really I needed to find a 2 kW inverter that could protect
      itself from a wind turbine. I would have had to connect more than one of
      my turbines to a 6 kW inverter to utilize its 6 kW capacity. I'm glad I
      at least have ONE of these reliable 6 kW US-made inverters for my own use!

      So the good news is that our turbines have finally been developed to the
      point that the furling is consistent and we never burn out stators anymore
      (knock on wood). So if we had a decent inverter, we might be able to
      offer a reliable grid-tie product, as a complete system, or maybe a kit
      for do-it-yourselfers and home-builders. And let's face it, "reliable" is
      the only thing that matters. A burnt or broken turbine (or inverter) does
      nobody any good, and burnt or broken is what quickly happens to most
      turbine installations (almost every single one of them - the fact that the
      veterans know and most people have no clue about).

      Anyway, some may remember that I had been e-mailed by a Chinese company
      producing a supposed German design inverter that allegedly featured
      overvoltage protection and overcurrent protection. They offered me a "2
      kW" inverter for a certain price in a quote on Sept 15, and I took the
      bait and wired funds to China. I'm used to working with reputable
      companies in China, so I felt fairly safe wiring funds over there.

      According to the company now, the inverter they sent was a 1.5 kW
      inverter, not the 2 kW inverter I ordered! Guess they were holding out...
      Hey, isn't that dishonest?

      Well the inverter I received DID feature overvoltage disconect/shutoff,
      and I even tested it by placing a generator on a lathe and hitting it with
      overvoltage. As advertised, the inverter "let go" of the generator,
      without damage, and re-engaged with the generator after the voltage
      dropped to acceptable levels. I ran one turbine into it here at my house
      for a couple of months, even in some horrendous winds, and it seemed fine.

      Then we brought this inverter out to one of our test sites, and connected
      it to a slightly more powerful turbine (still a SuperTwin(TM)). We waited
      about a week for any winds at all since we were in a calm period. The
      turbine spun up a few times, but there was not much in the way of winds.
      One day (still no wind) I got a call saying there was a permeating smell
      characteristic of an electrical fire in the shed out there at our test
      site. (Veterans know this smell.)

      A few days later we had some wind, and the turbine was acting like it was
      braked. As it turned out, the inverter was fried. We are puzzled as to
      how it could have fried when there were no winds to speak of. My
      supposition is that a single gust started up the turbine, and before the
      inverter had a chance to connect to the grid and load down the turbine, it
      produced a high voltage (running unloaded even in a light wind can
      generate high RPM and hence high voltage) and the overvoltage protection
      circuit did not catch it, with the result that multiple inverter
      components were melted and two capacitors were blown open. So as it
      appears, the overvoltage protection was not 100% reliable.

      The manufacturer in China, so far, has nothing to say except to recommend
      that I "replace the capacitors", and that "this is a 1.5 kW inverter".
      Only thing is, they quoted a 2 kW inverter, and I paid for a 2 kW
      inverter, and we discussed it as a 2 kW inverter for months before I
      bought it - bait and switch?

      Either way, if the inverter's overvoltage protection does not always work,
      then what good would a slightly larger inverter do us?

      Of course the company also offers an optional dump load controller with
      dump load. My question is, since a dump load is for protecting batteries
      from overcharging, and since this inverter supposedly can protect itself
      from overvoltage and overcurrent, why would one need a dump load? (Unless
      the overvoltage and overcurrent porotection were not reliable?)

      Anyway, I remain perplexed that the "small wind industry" seems no further
      along than when I first got into it 10 years ago.

      Sure, many companies claim to have reliable products, but show me who has
      a reliable installation, say one that has worked for 5 years without any
      trouble? Is there a single such trouble-free installation in the entire
      U.S.?

      Southwest Windpower, the market leader in sales, has recently sold off all
      its product lines except Skystream to other companies. That includes the
      Whisper line, including the Whisper 200 and 500 models, sold to a company
      in India that, according to inside information, is unable to produce a
      decent version of any Whisper turbine despite Southwest sending an
      engineer over there to help.

      And the "Air" models were sold to a company in Colorado that hired key
      Southwest personnel. If Southwest couldn't make any money on these
      models, why would a new company think they could? Every Air turbine I see
      in my travels is not working - they are everywhere!

      My question is, after 10 years of hand-waving and happy-talk about all
      these models and how wonderful they are, how could Southwest sell them
      off? According to them, they are in "survival mode". It seems that the
      company could not make any money on these turbines? And we know from
      previous discussions how many Skystreams out there are still having
      "issues" after all these years of development.

      The lesson I took away from watching Southwest was to not put out
      thousands of turbines until you were sure you had the bugs worked out.
      Otherwise you would be too bogged down fixing broken turbines, while
      getting further and further behind in these stacked-up repairs, and
      developing a bad name at least among the customers whose sites had too
      much wind for the Southwest models...

      And we keep hearing of all the boutiquey high-dollar choices with a
      European flavor, but it seems we seldom hear of a happy customer who has
      generated an economic return from these ultra-high-priced choices. Are
      they really reliable anyway? I mean, like a water-heater or washing
      machine, where you can figure on getting at least 5 years, maybe 10 or 15
      years, of trouble-free service before worrying about reliability at all?

      In the end, I wonder if maybe small wind, like wind energy in general, is
      just a bit too complicated for humans to handle. (We had a man on the
      moon before we had a windfarm.) I mean, after 10 years of beating my head
      against the wall, to realize that still, one of the main problems is that
      no grid-tie inverter for wind turbines even exists, tells me that all
      these programs to promote small wind have really missed the ball while
      swinging their large multi-million-dollar bat.

      It also brings to mind a question of what is the difference between a
      Barry Madoff and a Solyndra or even a Southwest? Is any of these
      companies really more than a Ponzi-scheme, with a green cloak for an
      excuse? One more way to get one more $10 million cash infusion band-aid?
      If they knew most of their products were not yet reliable, what's the
      excuse for selling them in the thousands? For telling investors to expect
      a profit? I've asked myself, is the only thing that separates a Ponzi
      scheme from a "legitimate money-losing company" the excuse that the
      company has a complicated story of how it supposedly is going to become
      profitable at some point?

      Anyway I am putting out the word to be careful whom you do business with,
      and under what conditions. A company that has no service capability in
      the U.S. will not be responsive to product failures. A company that
      cannot send the product that is paid for has bigger problems than the
      inevitable failure of its products, since without the basic integrity to
      ship what is ordered or to stand behind one's products, there is no hope
      of doing long-term business.

      Have a day!
      :)
      Doug S.





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    • Doug
      OK so you said peak of 55v - so when the turbine starts up... And the inverters begin sensing the grid... but not loading down the turbine yet... And the
      Message 2 of 11 , Mar 9, 2013
        OK so you said "peak of 55v" -
        so when the turbine starts up...
        And the inverters begin sensing the grid...
        but not loading down the turbine yet...
        And the turbine exceeds 55 Volts, being unloaded
        What happens to the inverter(s)?
        What happens if the wind is very strong and yo have a momentary high voltage event?
        What happens to these inverters when the grid goes down?
        Do these inverters have 3-phase input?
        No, well OK do they have overvoltage protection?
        Maybe I'm missing something but there doesn't seem to be anything new here except now you are using an inverter that is too small so you have to run a few together.
        You COULD use a 500-Watt inverter for a 2 kW turbine MOST of the time - well heck most of the time the wind is not even blowing. And you might be able to have a few inverters sequentially engage somehow as needed. But that doesn't seem to address the issue of no inverters designed for wind turbines being available.



        --- In small-wind-home@yahoogroups.com, Robert Bruninga <wb4apr@...> wrote:
        >
        > I have not been following this thread at all, but why not use solar
        > Microinverters?
        >
        > Use a noiminal 48v turbine and feed as many 24v solar microinverters in
        > series parallel are needed to handle the power? I see 500W microinverters
        > and they operate with a nominal 30v input (peak of 55v) So each pair in
        > series will give 1 kW and accept an input from below 48v up to 110v DC
        > (assuming their inputs are isolated).
        >
        > I am sure this has been discussed before, if so, don't shoot me. Just a
        > thought.
        > Bob, WB4aPR
        >
        > -----Original Message-----
        > From: small-wind-home@yahoogroups.com
        > [mailto:small-wind-home@yahoogroups.com] On Behalf Of Doug
        > Sent: Monday, February 11, 2013 12:11 PM
        > To: small-wind-home@yahoogroups.com
        > Subject: [s-w-h] Chinese Inverters - my latest failure
        >
        > Howdy all:
        > The regulars here may remember I had finally found a grid-tie inverter
        > made for wind turbines, made in USA, that rejected overvoltage rather than
        > being sizzled to a cinder. It was looking like we would finally be able
        > to offer a reloiable grid-tie home wind energy package.
        >
        > As it turned out, the U.S. company producing these over-voltage-proof
        > inverters went out-of-business right after I bought one, taken over by
        > Bergey who, according to Mike, had decided not to sell the inverters to
        > "competitors". (My thought was if I were buying these I could be thought
        > of as a "customer" rather than a "competitor". One thing I've learned in
        > business is you don't really know what products you make, that people
        > want, until the orders start coming in!)
        >
        > Anyway these U.S.-made 6 kW inverters are really overkill for my little 2
        > kW turbine, so really I needed to find a 2 kW inverter that could protect
        > itself from a wind turbine. I would have had to connect more than one of
        > my turbines to a 6 kW inverter to utilize its 6 kW capacity. I'm glad I
        > at least have ONE of these reliable 6 kW US-made inverters for my own use!
        >
        > So the good news is that our turbines have finally been developed to the
        > point that the furling is consistent and we never burn out stators anymore
        > (knock on wood). So if we had a decent inverter, we might be able to
        > offer a reliable grid-tie product, as a complete system, or maybe a kit
        > for do-it-yourselfers and home-builders. And let's face it, "reliable" is
        > the only thing that matters. A burnt or broken turbine (or inverter) does
        > nobody any good, and burnt or broken is what quickly happens to most
        > turbine installations (almost every single one of them - the fact that the
        > veterans know and most people have no clue about).
        >
        > Anyway, some may remember that I had been e-mailed by a Chinese company
        > producing a supposed German design inverter that allegedly featured
        > overvoltage protection and overcurrent protection. They offered me a "2
        > kW" inverter for a certain price in a quote on Sept 15, and I took the
        > bait and wired funds to China. I'm used to working with reputable
        > companies in China, so I felt fairly safe wiring funds over there.
        >
        > According to the company now, the inverter they sent was a 1.5 kW
        > inverter, not the 2 kW inverter I ordered! Guess they were holding out...
        > Hey, isn't that dishonest?
        >
        > Well the inverter I received DID feature overvoltage disconect/shutoff,
        > and I even tested it by placing a generator on a lathe and hitting it with
        > overvoltage. As advertised, the inverter "let go" of the generator,
        > without damage, and re-engaged with the generator after the voltage
        > dropped to acceptable levels. I ran one turbine into it here at my house
        > for a couple of months, even in some horrendous winds, and it seemed fine.
        >
        > Then we brought this inverter out to one of our test sites, and connected
        > it to a slightly more powerful turbine (still a SuperTwin(TM)). We waited
        > about a week for any winds at all since we were in a calm period. The
        > turbine spun up a few times, but there was not much in the way of winds.
        > One day (still no wind) I got a call saying there was a permeating smell
        > characteristic of an electrical fire in the shed out there at our test
        > site. (Veterans know this smell.)
        >
        > A few days later we had some wind, and the turbine was acting like it was
        > braked. As it turned out, the inverter was fried. We are puzzled as to
        > how it could have fried when there were no winds to speak of. My
        > supposition is that a single gust started up the turbine, and before the
        > inverter had a chance to connect to the grid and load down the turbine, it
        > produced a high voltage (running unloaded even in a light wind can
        > generate high RPM and hence high voltage) and the overvoltage protection
        > circuit did not catch it, with the result that multiple inverter
        > components were melted and two capacitors were blown open. So as it
        > appears, the overvoltage protection was not 100% reliable.
        >
        > The manufacturer in China, so far, has nothing to say except to recommend
        > that I "replace the capacitors", and that "this is a 1.5 kW inverter".
        > Only thing is, they quoted a 2 kW inverter, and I paid for a 2 kW
        > inverter, and we discussed it as a 2 kW inverter for months before I
        > bought it - bait and switch?
        >
        > Either way, if the inverter's overvoltage protection does not always work,
        > then what good would a slightly larger inverter do us?
        >
        > Of course the company also offers an optional dump load controller with
        > dump load. My question is, since a dump load is for protecting batteries
        > from overcharging, and since this inverter supposedly can protect itself
        > from overvoltage and overcurrent, why would one need a dump load? (Unless
        > the overvoltage and overcurrent porotection were not reliable?)
        >
        > Anyway, I remain perplexed that the "small wind industry" seems no further
        > along than when I first got into it 10 years ago.
        >
        > Sure, many companies claim to have reliable products, but show me who has
        > a reliable installation, say one that has worked for 5 years without any
        > trouble? Is there a single such trouble-free installation in the entire
        > U.S.?
        >
        > Southwest Windpower, the market leader in sales, has recently sold off all
        > its product lines except Skystream to other companies. That includes the
        > Whisper line, including the Whisper 200 and 500 models, sold to a company
        > in India that, according to inside information, is unable to produce a
        > decent version of any Whisper turbine despite Southwest sending an
        > engineer over there to help.
        >
        > And the "Air" models were sold to a company in Colorado that hired key
        > Southwest personnel. If Southwest couldn't make any money on these
        > models, why would a new company think they could? Every Air turbine I see
        > in my travels is not working - they are everywhere!
        >
        > My question is, after 10 years of hand-waving and happy-talk about all
        > these models and how wonderful they are, how could Southwest sell them
        > off? According to them, they are in "survival mode". It seems that the
        > company could not make any money on these turbines? And we know from
        > previous discussions how many Skystreams out there are still having
        > "issues" after all these years of development.
        >
        > The lesson I took away from watching Southwest was to not put out
        > thousands of turbines until you were sure you had the bugs worked out.
        > Otherwise you would be too bogged down fixing broken turbines, while
        > getting further and further behind in these stacked-up repairs, and
        > developing a bad name at least among the customers whose sites had too
        > much wind for the Southwest models...
        >
        > And we keep hearing of all the boutiquey high-dollar choices with a
        > European flavor, but it seems we seldom hear of a happy customer who has
        > generated an economic return from these ultra-high-priced choices. Are
        > they really reliable anyway? I mean, like a water-heater or washing
        > machine, where you can figure on getting at least 5 years, maybe 10 or 15
        > years, of trouble-free service before worrying about reliability at all?
        >
        > In the end, I wonder if maybe small wind, like wind energy in general, is
        > just a bit too complicated for humans to handle. (We had a man on the
        > moon before we had a windfarm.) I mean, after 10 years of beating my head
        > against the wall, to realize that still, one of the main problems is that
        > no grid-tie inverter for wind turbines even exists, tells me that all
        > these programs to promote small wind have really missed the ball while
        > swinging their large multi-million-dollar bat.
        >
        > It also brings to mind a question of what is the difference between a
        > Barry Madoff and a Solyndra or even a Southwest? Is any of these
        > companies really more than a Ponzi-scheme, with a green cloak for an
        > excuse? One more way to get one more $10 million cash infusion band-aid?
        > If they knew most of their products were not yet reliable, what's the
        > excuse for selling them in the thousands? For telling investors to expect
        > a profit? I've asked myself, is the only thing that separates a Ponzi
        > scheme from a "legitimate money-losing company" the excuse that the
        > company has a complicated story of how it supposedly is going to become
        > profitable at some point?
        >
        > Anyway I am putting out the word to be careful whom you do business with,
        > and under what conditions. A company that has no service capability in
        > the U.S. will not be responsive to product failures. A company that
        > cannot send the product that is paid for has bigger problems than the
        > inevitable failure of its products, since without the basic integrity to
        > ship what is ordered or to stand behind one's products, there is no hope
        > of doing long-term business.
        >
        > Have a day!
        > :)
        > Doug S.
        >
        >
        >
        >
        >
        > ------------------------------------
        >
        > ==========================================================
        > THANK YOU FOR PARTICIPATING IN THE HOME ENERGY LIST.
        > ----------------------------------------------------------
        > . Please feel free to send your input to:
        > small-wind-home@yahoogroups.com
        > . Join the list by sending a blank e-mail to:
        > small-wind-home-subscribe@yahoogroups.com
        > . To view previous messages from the list,
        > subscribe to a daily digest of the list,
        > or stop receiving the list by e-mail
        > (and read it on the Web), go to
        > http://www.yahoogroups.com/list/small-wind-home .
        > . An FAQ on small wind systems is located at
        > http://www.ndsu.nodak.edu/ndsu/klemen .
        >
        > ----------------------------------------------------------
        > Yahoo! Groups Links
        >
      • Tobias Gogolin
        I doubt you d get happy with inverters in series! Sounds like a recipe for failure to me! There is no guarantee they would share the voltage symmetrically! I
        Message 3 of 11 , Mar 9, 2013
          I doubt you'd get happy with inverters in series! Sounds like a recipe for
          failure to me! There is no guarantee they would share the voltage
          symmetrically! I also would recommend against such low voltage generators!
          There is always a way to multiply the voltage while rectifying if the
          windings were indeed low voltage! If there is any significant power
          produced on low voltage you'd have to invest unreasonably in copper! And
          that would be a very vulnerable part of your system because in crisis
          situations thief's collect these semi precious metals with much preference!
          If you want to be able to have the generator far from your house you need
          to go to a few hundred volts DC and get the highest voltage inverter you
          can find! To be sure that over-voltage wont cause problems develop a
          dump-load circuit possibly with multiple progressive outputs and loads! One
          thing for sure a Generator will furl into protection better if it resists
          the wind somewhat! Unloaded over-spinning is dangerous for the whole
          system, and it needs to be avoided!
          I trust my intuition, but I'm willing to be corrected if I err!


          cheers!


          On Sat, Mar 9, 2013 at 6:28 AM, Doug <dougselsam@...> wrote:

          > OK so you said "peak of 55v" -
          > so when the turbine starts up...
          > And the inverters begin sensing the grid...
          > but not loading down the turbine yet...
          > And the turbine exceeds 55 Volts, being unloaded
          > What happens to the inverter(s)?
          > What happens if the wind is very strong and yo have a momentary high
          > voltage event?
          > What happens to these inverters when the grid goes down?
          > Do these inverters have 3-phase input?
          > No, well OK do they have overvoltage protection?
          > Maybe I'm missing something but there doesn't seem to be anything new here
          > except now you are using an inverter that is too small so you have to run a
          > few together.
          > You COULD use a 500-Watt inverter for a 2 kW turbine MOST of the time -
          > well heck most of the time the wind is not even blowing. And you might be
          > able to have a few inverters sequentially engage somehow as needed. But
          > that doesn't seem to address the issue of no inverters designed for wind
          > turbines being available.
          >
          >
          >
          > --- In small-wind-home@yahoogroups.com, Robert Bruninga <wb4apr@...>
          > wrote:
          > >
          > > I have not been following this thread at all, but why not use solar
          > > Microinverters?
          > >
          > > Use a noiminal 48v turbine and feed as many 24v solar microinverters in
          > > series parallel are needed to handle the power? I see 500W
          > microinverters
          > > and they operate with a nominal 30v input (peak of 55v) So each pair in
          > > series will give 1 kW and accept an input from below 48v up to 110v DC
          > > (assuming their inputs are isolated).
          > >
          > > I am sure this has been discussed before, if so, don't shoot me. Just a
          > > thought.
          > > Bob, WB4aPR
          > >
          > > -----Original Message-----
          > > From: small-wind-home@yahoogroups.com
          > > [mailto:small-wind-home@yahoogroups.com] On Behalf Of Doug
          > > Sent: Monday, February 11, 2013 12:11 PM
          > > To: small-wind-home@yahoogroups.com
          > > Subject: [s-w-h] Chinese Inverters - my latest failure
          > >
          > > Howdy all:
          > > The regulars here may remember I had finally found a grid-tie inverter
          > > made for wind turbines, made in USA, that rejected overvoltage rather
          > than
          > > being sizzled to a cinder. It was looking like we would finally be able
          > > to offer a reloiable grid-tie home wind energy package.
          > >
          > > As it turned out, the U.S. company producing these over-voltage-proof
          > > inverters went out-of-business right after I bought one, taken over by
          > > Bergey who, according to Mike, had decided not to sell the inverters to
          > > "competitors". (My thought was if I were buying these I could be thought
          > > of as a "customer" rather than a "competitor". One thing I've learned in
          > > business is you don't really know what products you make, that people
          > > want, until the orders start coming in!)
          > >
          > > Anyway these U.S.-made 6 kW inverters are really overkill for my little 2
          > > kW turbine, so really I needed to find a 2 kW inverter that could protect
          > > itself from a wind turbine. I would have had to connect more than one of
          > > my turbines to a 6 kW inverter to utilize its 6 kW capacity. I'm glad I
          > > at least have ONE of these reliable 6 kW US-made inverters for my own
          > use!
          > >
          > > So the good news is that our turbines have finally been developed to the
          > > point that the furling is consistent and we never burn out stators
          > anymore
          > > (knock on wood). So if we had a decent inverter, we might be able to
          > > offer a reliable grid-tie product, as a complete system, or maybe a kit
          > > for do-it-yourselfers and home-builders. And let's face it, "reliable"
          > is
          > > the only thing that matters. A burnt or broken turbine (or inverter)
          > does
          > > nobody any good, and burnt or broken is what quickly happens to most
          > > turbine installations (almost every single one of them - the fact that
          > the
          > > veterans know and most people have no clue about).
          > >
          > > Anyway, some may remember that I had been e-mailed by a Chinese company
          > > producing a supposed German design inverter that allegedly featured
          > > overvoltage protection and overcurrent protection. They offered me a "2
          > > kW" inverter for a certain price in a quote on Sept 15, and I took the
          > > bait and wired funds to China. I'm used to working with reputable
          > > companies in China, so I felt fairly safe wiring funds over there.
          > >
          > > According to the company now, the inverter they sent was a 1.5 kW
          > > inverter, not the 2 kW inverter I ordered! Guess they were holding out...
          > > Hey, isn't that dishonest?
          > >
          > > Well the inverter I received DID feature overvoltage disconect/shutoff,
          > > and I even tested it by placing a generator on a lathe and hitting it
          > with
          > > overvoltage. As advertised, the inverter "let go" of the generator,
          > > without damage, and re-engaged with the generator after the voltage
          > > dropped to acceptable levels. I ran one turbine into it here at my house
          > > for a couple of months, even in some horrendous winds, and it seemed
          > fine.
          > >
          > > Then we brought this inverter out to one of our test sites, and connected
          > > it to a slightly more powerful turbine (still a SuperTwin(TM)). We
          > waited
          > > about a week for any winds at all since we were in a calm period. The
          > > turbine spun up a few times, but there was not much in the way of winds.
          > > One day (still no wind) I got a call saying there was a permeating smell
          > > characteristic of an electrical fire in the shed out there at our test
          > > site. (Veterans know this smell.)
          > >
          > > A few days later we had some wind, and the turbine was acting like it was
          > > braked. As it turned out, the inverter was fried. We are puzzled as to
          > > how it could have fried when there were no winds to speak of. My
          > > supposition is that a single gust started up the turbine, and before the
          > > inverter had a chance to connect to the grid and load down the turbine,
          > it
          > > produced a high voltage (running unloaded even in a light wind can
          > > generate high RPM and hence high voltage) and the overvoltage protection
          > > circuit did not catch it, with the result that multiple inverter
          > > components were melted and two capacitors were blown open. So as it
          > > appears, the overvoltage protection was not 100% reliable.
          > >
          > > The manufacturer in China, so far, has nothing to say except to recommend
          > > that I "replace the capacitors", and that "this is a 1.5 kW inverter".
          > > Only thing is, they quoted a 2 kW inverter, and I paid for a 2 kW
          > > inverter, and we discussed it as a 2 kW inverter for months before I
          > > bought it - bait and switch?
          > >
          > > Either way, if the inverter's overvoltage protection does not always
          > work,
          > > then what good would a slightly larger inverter do us?
          > >
          > > Of course the company also offers an optional dump load controller with
          > > dump load. My question is, since a dump load is for protecting batteries
          > > from overcharging, and since this inverter supposedly can protect itself
          > > from overvoltage and overcurrent, why would one need a dump load?
          > (Unless
          > > the overvoltage and overcurrent porotection were not reliable?)
          > >
          > > Anyway, I remain perplexed that the "small wind industry" seems no
          > further
          > > along than when I first got into it 10 years ago.
          > >
          > > Sure, many companies claim to have reliable products, but show me who has
          > > a reliable installation, say one that has worked for 5 years without any
          > > trouble? Is there a single such trouble-free installation in the entire
          > > U.S.?
          > >
          > > Southwest Windpower, the market leader in sales, has recently sold off
          > all
          > > its product lines except Skystream to other companies. That includes the
          > > Whisper line, including the Whisper 200 and 500 models, sold to a company
          > > in India that, according to inside information, is unable to produce a
          > > decent version of any Whisper turbine despite Southwest sending an
          > > engineer over there to help.
          > >
          > > And the "Air" models were sold to a company in Colorado that hired key
          > > Southwest personnel. If Southwest couldn't make any money on these
          > > models, why would a new company think they could? Every Air turbine I
          > see
          > > in my travels is not working - they are everywhere!
          > >
          > > My question is, after 10 years of hand-waving and happy-talk about all
          > > these models and how wonderful they are, how could Southwest sell them
          > > off? According to them, they are in "survival mode". It seems that the
          > > company could not make any money on these turbines? And we know from
          > > previous discussions how many Skystreams out there are still having
          > > "issues" after all these years of development.
          > >
          > > The lesson I took away from watching Southwest was to not put out
          > > thousands of turbines until you were sure you had the bugs worked out.
          > > Otherwise you would be too bogged down fixing broken turbines, while
          > > getting further and further behind in these stacked-up repairs, and
          > > developing a bad name at least among the customers whose sites had too
          > > much wind for the Southwest models...
          > >
          > > And we keep hearing of all the boutiquey high-dollar choices with a
          > > European flavor, but it seems we seldom hear of a happy customer who has
          > > generated an economic return from these ultra-high-priced choices. Are
          > > they really reliable anyway? I mean, like a water-heater or washing
          > > machine, where you can figure on getting at least 5 years, maybe 10 or 15
          > > years, of trouble-free service before worrying about reliability at all?
          > >
          > > In the end, I wonder if maybe small wind, like wind energy in general, is
          > > just a bit too complicated for humans to handle. (We had a man on the
          > > moon before we had a windfarm.) I mean, after 10 years of beating my
          > head
          > > against the wall, to realize that still, one of the main problems is that
          > > no grid-tie inverter for wind turbines even exists, tells me that all
          > > these programs to promote small wind have really missed the ball while
          > > swinging their large multi-million-dollar bat.
          > >
          > > It also brings to mind a question of what is the difference between a
          > > Barry Madoff and a Solyndra or even a Southwest? Is any of these
          > > companies really more than a Ponzi-scheme, with a green cloak for an
          > > excuse? One more way to get one more $10 million cash infusion band-aid?
          > > If they knew most of their products were not yet reliable, what's the
          > > excuse for selling them in the thousands? For telling investors to
          > expect
          > > a profit? I've asked myself, is the only thing that separates a Ponzi
          > > scheme from a "legitimate money-losing company" the excuse that the
          > > company has a complicated story of how it supposedly is going to become
          > > profitable at some point?
          > >
          > > Anyway I am putting out the word to be careful whom you do business with,
          > > and under what conditions. A company that has no service capability in
          > > the U.S. will not be responsive to product failures. A company that
          > > cannot send the product that is paid for has bigger problems than the
          > > inevitable failure of its products, since without the basic integrity to
          > > ship what is ordered or to stand behind one's products, there is no hope
          > > of doing long-term business.
          > >
          > > Have a day!
          > > :)
          > > Doug S.
          > >
          > >
          > >
          > >
          > >
          > > ------------------------------------
          > >
          > > ==========================================================
          > > THANK YOU FOR PARTICIPATING IN THE HOME ENERGY LIST.
          > > ----------------------------------------------------------
          > > . Please feel free to send your input to:
          > > small-wind-home@yahoogroups.com
          > > . Join the list by sending a blank e-mail to:
          > > small-wind-home-subscribe@yahoogroups.com
          > > . To view previous messages from the list,
          > > subscribe to a daily digest of the list,
          > > or stop receiving the list by e-mail
          > > (and read it on the Web), go to
          > > http://www.yahoogroups.com/list/small-wind-home .
          > > . An FAQ on small wind systems is located at
          > > http://www.ndsu.nodak.edu/ndsu/klemen .
          > >
          > > ----------------------------------------------------------
          > > Yahoo! Groups Links
          > >
          >
          >
          >
          >
          > ------------------------------------
          >
          > ==========================================================
          > THANK YOU FOR PARTICIPATING IN THE HOME ENERGY LIST.
          > ----------------------------------------------------------
          > . Please feel free to send your input to:
          > small-wind-home@yahoogroups.com
          > . Join the list by sending a blank e-mail to:
          > small-wind-home-subscribe@yahoogroups.com
          > . To view previous messages from the list,
          > subscribe to a daily digest of the list,
          > or stop receiving the list by e-mail
          > (and read it on the Web), go to
          > http://www.yahoogroups.com/list/small-wind-home .
          > . An FAQ on small wind systems is located at
          > http://www.ndsu.nodak.edu/ndsu/klemen .
          >
          > ----------------------------------------------------------
          > Yahoo! Groups Links
          >
          >
          >
          >


          --
          Tobias Gogolin
          Tel. Movistar (646) 124 32 82
          Tel. Telcel (646) 160 58 99
          skype: moontogo
          messenger: usertogo@...
          First Bitcoin Account: 1LCupcVd8HhAGyVhd3xayPpnQHeis7rAiV
          Blog: http://zeitgeistensenada.blogspot.com/

          You develop Sustainable Ranch Technology at
          http://tech.groups.yahoo.com/group/SURA-TECH
          an Open Source Electric Motor/Alternator at
          http://groups.yahoo.com/group/Performance_Axial_Flux
          and an Open Source Motor Controller at http://groups.yahoo.com/group/GoBox


          [Non-text portions of this message have been removed]
        • Doug
          Unloaded overspinning does not seem to be a problem for a turbine that furls properly. The Bergey 10 kW system handles excessively-high winds in this way and
          Message 4 of 11 , Mar 10, 2013
            Unloaded overspinning does not seem to be a problem for a turbine that furls properly. The Bergey 10 kW system handles excessively-high winds in this way and almost stops while unloaded and sideways. Then it falls back into the wind and goes fast again, then turns sideways and goes slow again.
            Maybe if your furling turbine needs a dump load it is not furling well enough and will burn out.(?)
            Seems to me the first item on an effective small wind agenda is to identify any model of turbine that is consistently reliable and doesn't break down or burn out, throw blades, etc.
            The resulting list of turbines could probably be counted on one hand.
            One finger?

            --- In small-wind-home@yahoogroups.com, Tobias Gogolin <usertogo@...> wrote:
            >
            > I doubt you'd get happy with inverters in series! Sounds like a recipe for
            > failure to me! There is no guarantee they would share the voltage
            > symmetrically! I also would recommend against such low voltage generators!
            > There is always a way to multiply the voltage while rectifying if the
            > windings were indeed low voltage! If there is any significant power
            > produced on low voltage you'd have to invest unreasonably in copper! And
            > that would be a very vulnerable part of your system because in crisis
            > situations thief's collect these semi precious metals with much preference!
            > If you want to be able to have the generator far from your house you need
            > to go to a few hundred volts DC and get the highest voltage inverter you
            > can find! To be sure that over-voltage wont cause problems develop a
            > dump-load circuit possibly with multiple progressive outputs and loads! One
            > thing for sure a Generator will furl into protection better if it resists
            > the wind somewhat! Unloaded over-spinning is dangerous for the whole
            > system, and it needs to be avoided!
            > I trust my intuition, but I'm willing to be corrected if I err!
            >
            >
            > cheers!
          • Tobias Gogolin
            The turbine I modified for higher woltages (was 24 V 3 phase = now is 200-300 V at reasonable low RPM could even be dammaged due to overvoltage ( 600V
            Message 5 of 11 , Mar 10, 2013
              The turbine I modified for higher woltages (was 24 V 3 phase => now is
              200-300 V at reasonable low RPM could even be dammaged due to overvoltage
              (>600V capacitors might blow)). High RPM will even produce possibly
              excessive voltage on unmodified systems. If the electric brake could be
              applied, I'm sure there is less stress on the hardware than at very high
              RPM! If the electric brake ever fails its still early enough to find out if
              the furling will also work when overspinning!

              On Sun, Mar 10, 2013 at 6:29 AM, Doug <dougselsam@...> wrote:

              > Unloaded overspinning does not seem to be a problem for a turbine that
              > furls properly. The Bergey 10 kW system handles excessively-high winds in
              > this way and almost stops while unloaded and sideways. Then it falls back
              > into the wind and goes fast again, then turns sideways and goes slow again.
              > Maybe if your furling turbine needs a dump load it is not furling well
              > enough and will burn out.(?)
              > Seems to me the first item on an effective small wind agenda is to
              > identify any model of turbine that is consistently reliable and doesn't
              > break down or burn out, throw blades, etc.
              > The resulting list of turbines could probably be counted on one hand.
              > One finger?
              >
              > --- In small-wind-home@yahoogroups.com, Tobias Gogolin <usertogo@...>
              > wrote:
              > >
              > > I doubt you'd get happy with inverters in series! Sounds like a recipe
              > for
              > > failure to me! There is no guarantee they would share the voltage
              > > symmetrically! I also would recommend against such low voltage
              > generators!
              > > There is always a way to multiply the voltage while rectifying if the
              > > windings were indeed low voltage! If there is any significant power
              > > produced on low voltage you'd have to invest unreasonably in copper! And
              > > that would be a very vulnerable part of your system because in crisis
              > > situations thief's collect these semi precious metals with much
              > preference!
              > > If you want to be able to have the generator far from your house you need
              > > to go to a few hundred volts DC and get the highest voltage inverter you
              > > can find! To be sure that over-voltage wont cause problems develop a
              > > dump-load circuit possibly with multiple progressive outputs and loads!
              > One
              > > thing for sure a Generator will furl into protection better if it resists
              > > the wind somewhat! Unloaded over-spinning is dangerous for the whole
              > > system, and it needs to be avoided!
              > > I trust my intuition, but I'm willing to be corrected if I err!
              > >
              > >
              > > cheers!
              >
              >
              >
              >
              > ------------------------------------
              >
              > ==========================================================
              > THANK YOU FOR PARTICIPATING IN THE HOME ENERGY LIST.
              > ----------------------------------------------------------
              > . Please feel free to send your input to:
              > small-wind-home@yahoogroups.com
              > . Join the list by sending a blank e-mail to:
              > small-wind-home-subscribe@yahoogroups.com
              > . To view previous messages from the list,
              > subscribe to a daily digest of the list,
              > or stop receiving the list by e-mail
              > (and read it on the Web), go to
              > http://www.yahoogroups.com/list/small-wind-home .
              > . An FAQ on small wind systems is located at
              > http://www.ndsu.nodak.edu/ndsu/klemen .
              >
              > ----------------------------------------------------------
              > Yahoo! Groups Links
              >
              >
              >
              >


              --
              Tobias Gogolin
              Tel. Movistar (646) 124 32 82
              Tel. Telcel (646) 160 58 99
              skype: moontogo
              messenger: usertogo@...
              First Bitcoin Account: 1LCupcVd8HhAGyVhd3xayPpnQHeis7rAiV
              Blog: http://zeitgeistensenada.blogspot.com/

              You develop Sustainable Ranch Technology at
              http://tech.groups.yahoo.com/group/SURA-TECH
              an Open Source Electric Motor/Alternator at
              http://groups.yahoo.com/group/Performance_Axial_Flux
              and an Open Source Motor Controller at http://groups.yahoo.com/group/GoBox


              [Non-text portions of this message have been removed]
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