Hydraulically operated wind wurbine towers

[poco dinero]

I recently purchased two 40 foot tall, hydraulically-operated wind turbine towers.  They are rated for up to 10 kw turbines, but I plan to add another 15 feet to them and mount an Exmork 2.5 kw wind turbine on each tower.

I wasn't sure what I would get, but these towers are beautiful.  Each tower came with a huge compound hydraulic cylinder that looked as if it fell off a D10 Caterpiller ripper.  They also came with 14 six foot long 1 1/4 inch diameter foundation bolts, and a set of 1/4 inch steel "position boards" to be used for setting the foundation bolts for the tower base and the cylinder base mount.

I plan to raise and lower the towers using the hydraulic system on my Kubota tractor, but if you don't have a tractor the Chinese will sell you a hydraulic pump for a few extra bucks.

You can see a picture of these towers on the Shenzhou company's website. which is

          http://www.f-n.cn/

You can also request a price quote using their web site ($3066 including shipping from China to Los Angeles).

I actually didn't buy my towers directly from the Shenzhou factory; I got mine through Allen at Applied Magnetics in Plano, Texas.  For a few extra bucks he took care of ordering them, getting them shipped, unloaded and processed through customs in LA.  He sent me a delivery order, and when I presented that to the warehouse in LA they loaded the towers onto my trailer and I was back on the road in half an hour.  Worked slick.

It does work well to buy directly from Chinese factories, however.  I bought my three Exmork wind turbines using Exmork's web site.  Exmork doesn't post prices on their website, but if you email them James Ye will send you the price list for their entire product line.  And you will be astounded.  A 2.5 kw wind turbine for only $575.  A matched 2.5 kw MPPT controller, dump load controller, and 3000 watt dump load for $165.  I told James that I wanted to buy an extra set of bearings, and an extra nose cone (for use on my DanB 10 footer), and he said those items would be free.  I'm going to use the bearings to try to find an identical set of Timken bearings.  I like those Exmork folks.

I also have an Exmork 5 kw wind turbine.  What a beast.  Weighs 357 kg (785 lbs.)  It has a drum brake inside the housing that is activated by pulling a cable from the ground.  All Exmork wind turbines use slip rings.

I'm recovering from surgery so haven't had time to fly any of this stuff.  Looking forward to it though.

Poco

"They say when you get old, the second thing to go is your memory, and I can't remember what the first thing is".

[Ungrounded Lightning Rod]

Nice idea.

I REALLY don't like the shiny piston rod being exposed in the normal position.  If that's not stainless (or even if it is) I'd want some kind of cover over it to protect it from the elements - and thus protect the seals when you let it down some day.

[opo]

I think that once the tower is up and the botom of the pipe is bolted the piston(s) can be removed and stored for later use.

Octavio

[fabricator]

Yeah, you raise the tower onto a flange with studs in it and bolt it down then the cylinder is removed, the flange on the tower has elongated holes to make up for the radius as the hinge closes.

[jwilson]

Canadian company Re-Driven has hydraulic towers http://www.redriven.ca/

[poco dinero]

UGL,

The piston rods look like polished chrome, similar to my old John Deere backhoe, which has been sitting outside in the weather for at least forty years and they haven't rusted.  I plan to cover them though, and carefully clean them before operating the cylinders.

[poco dinero]

ULR,

The piston rods look like polished chrome, just like the cylinders om my old John Deere backhoe, which has been sitting out in the weather for 35 years and they haven't rusted.  I do plan to cover them though, and carefully clean them before lowering the tower.

[poco dinero]

ULR,

The piston rods look like ground and polished chrome, just like the cylinders on my old John Deere backhoe, which has been sitting out in the sun for 35 years or so, and they haven't rusted.  I do plan to cover them though, and carefully clean them before lowering the towers.  I also plan to protect the hoses; you wouldn't want a hose to fail when the tower was half way down.

[poco dinero]

Octavio,

You wouldn't want to move these cylinders too many times.  They must weigh 400 lbs.

[poco dinero]

ULR,

The piston rods are ground and polished chrome plated steel, just like the cylinders on my old John Deere backhoe, which has been sitting out in the weather for 35-40 years, and they haven't rusted.  I do plan to cover them though, and carefully clean them before lowering the tower.  I also plan to protect the hoses, you wouldn't want a hose to fail when the tower was halfway down.

Octavio,

You wouldn't want to move these cylinders very often, they must weigh 400 pounds.

jwilson,

I believe those Re-driven towers are made by this same Chinese company, Shenzhou.

poco

[defed]

there are quite a few videos of this type of tower on youtube.  i watched a bunch when i was looking for vids on raising w/ a gin pole.

i thought, briefly, about making my 3 leg rohn raise by hydraulics (2 cylinders, 1 on each of two legs), but not so sure that the 2.5" pipe could handle the forces.  maybe if i had 10' or 15' long cylinders to reduce the stress!

[pilot68b]

I want to buy an Exmork 2.5KW, but I hate to send money to someone overseas I never met. Can you email me and let me know what your experience was like and how you arranged payment.

John

[poco dinero]

John,

I can understand your concern about sending money blindly overseas, I felt the same way the first time.  You sure wouldn't  be able to sue to get it back.

But it worked great.  After James Ye sent me the price list, I decided to tryout the process.  When I told James that I wanted to proceed with the purchase of the Exmork 5 kw 48 volt machine, he sent me a "proforma invoice" and wiring instructions to route the money to his bank.  He told me to only send half the money, and that he would then get my order shipped and send me a "Bill of Lading", after which I was to send the rest of the money.

So I sent the wife off to Wells Fargo, and they wired the money.  When we emailed James that the money had been wired, he emailed back that he would like a copy of the wiring receipt, so we emailed a copy to him.  About ten days later we received the Bill of Lading; it showed what was shipped and even the name of the ship that was bringing our wind turbine to us and the date it was expected to arrive in Los Angeles.  We were able to go to the shipping company's website and follow the ship across the ocean.  Came on the HYUNDAI CHALLENGER.

Freight from China is really cheap.  With crating that 5 kw weighed over 1000 lbs, the shipping was only $150.  And those ships must really put the petal to the metal; less than three weeks to cross the Pacific.

Anyway, I asked James about US Customs, and he said that his agent in Los Angeles would "help" clear customs.  I wasn't sure what that meant, but when I got to LA the 6 packages were all cleared and ready for pickup.  The packaging had all been  broken into by US Customs and resealed with yellow customs tape.

I was headed back home to New Harmony, Utah in about an hour.  It worked slick.

Do I trust Exmork?  Absolutely.  Did you notice in my original post that when I told James that I wanted to buy a spare set of bearings for the 2.5 kw and the 5 kw, as well as an Exmork fiberglass nose cone for use on my DanB 10 footer, he said those items would be FREEEEEE.

Incidently, the Exmork 2.5 kw and the Exmork 2.0 kw turbines are the exact same machine.  The 2 kw is rated 2 kw at 22 mph wind speed; and the 2.5 kw is rated at 2.5 kw at 27 mph wind speed.  Either one will put out 3.6 kw if the wind blows hard enough; then the controller starts applying dynamic braking and the machine yaws to limit and in fact, reduce the output.  Survival wind speed is 110 mph.  Works for me.

If you buy the wind turbine, be sure to also buy the controller.  Besides controlling the speed and output of the wind turbine, it also includes the dump load controller, the kill switch (shorts the three phases together), and a 4 kw dump load.

Exmork has a really interesting furling system, different from everybody else.  On the 5 kw machine the yaw axis offset is only 3 1/4 inches, whereas the rotor diameter is almost 17 feet.  The tail boom doesn't fold up like the Otherpower designs; instead the tail feather rotates about an inclined axis and reduces its cross sectiom to the wind.  The neat thing about this is that if you want your machine to run faster you can reduce the axis inclination angle.  If you want it to run slower, you can increase the axis inclination angle.  On the 5kw machine, the prop pitch is also adjustable (but not controllable during flight).  The standard setting is about a TSR 6 setting, but if you have really strong or weak winds you can dial in whatever TSR you want.

I'm totally satisfied with my machines and with the company.  If Walmart sold wind turbines, this is what they would sell.  And can you believe $575 for a 2.5 kw wind turbine with a rotor diameter of 3.8 meters (12.5 feet).

Now you gotta get one of those Hangzhou Shenzhou hydraukic towers.  Only $3066 including shipment to Los Angeles.

[pilot68b]

Thanks getting back to me. Your words where encouraging. I contacted James and got the ball rolling. I'm buying two 2.5kw, one to fly and the other as back-up or parts. For that price you can't go wrong. I have a few questions. How are you going to use the 2.5kw and 5kw with 48V. I just want to sell back to the lazy ass power company. What type off Inverter are you using. What pipe size do they recommend for the 2.5KW mount.

John

[fabricator]

If you want to sell back to the power company you will have to buy a real inverter.

[pilot68b]

what do you consider a real Inverter.

[TomW]

what do you consider a real Inverter.

Well, for one thing it would require a UL approval [sticker] to legally connect to the grid here in the US anyway. I did not see anyone claim that existed?

This thread seems to have turned into a how great the Chinese equipment is thread.  I hope folks see the other side of the coin as well.

You are new here so please forgive if some [read I] might get suspicious when they see comments on how great something commercial is from new folks.

We are targeted by SPAM on all levels.

Poisoned pets, toxic materials, stolen designs, faked compliance documentation all have come from China recently in their headlong rush to global commerce. I just find it hard to trust them or their products. But that is just my view.

I will leave it at that.

Tom

[poco dinero]

John,

I have a (legally) grid-tied Xantrex 6048 Inverter that is supported by a 490 AH bank of DEKA AGM batteries.  No battery maintenance.  Right now that Xantrex is receiving the output of a 1.5 kw PV array, leaving 4.5 kw of unused inverter capacity, as long as the grid stays up.  If the grid goes down, that extra capac ity is used for backup, drawing energy out of the battery bank.

As I indicated in my original post, the two 2.5 kw 48 volt Exmorks will be installed on the two hydraulic towers, and they will feed their power directly to that 48 volt 490 AH battery bank (through their own wind turbine controllers).  From there it will go directly to the Xantrex 6048 inverter, thereby using up that excess inverter capacity when the grid is active.  If the wind blows and the sun shines I could be sending 6 kw to the grid, with the rest of the power generated by the wind turbines going to their dump loads (air heaters).

Incidentally, I am in really great wind area, high on a ridge on the rim of the Great Basin, at 5500 feet altitude.  There is a huge commercial wind farm about twenty miles north of my place, and another huge one going in six miles north of me.  Thankfully they are both downwind of me, at least for the prevailing southwest winds.

Here is my eventual plan for the Exmork 5kw 48 volt machine.  First of all, I'm in the process of buying a second 5 kw 48 volt machine.  I am trying to make my place totally energy independent.  I have installed  a 12 foot x 24 foot drain-back solar heat collecting system on the south side of my shop building, ala garygary's system at BuiltItSolar.com.  

Eventually I'm going to take down those two 2.5 kw machines and put up the fives.  Obviously on windy days they will overwhelm the Xantrex 6048, and dump the excess power to a dump load.  I am going to install about ten kw of water heaters in my 880 gallon drainback tank, and use that as a dump load instead of the air-heating dump loads supplied by the Chinese.  I will use the air dumps in the summer, the water heaters in the winter.  My house has radiant heat.

Eventually I might want to expand my inverter capacity and sell more power to the grid.  I believe the day is coming when FIT (feed-in tariffs) will be the law of the land.  Under FIT's the power company will be required to buy my power at 4 or 5 times the going rate.  That will shorten the payback time immensely.

I believe, but am not 100% sure, that the Exmork 2.5 kw machines mount directly to a 3 inch Schedule 40 iron pipe.

poco

[cdog]

Could you post some pics with a more detailed explanation of the 5kw furling system, quite interesting,

Cdog.

[poco dinero]

ForPilot86b

John,

I didn't get a chance to completely answer your questions because I had to leave for a doctor's appointment, so here goes more rambling.

The Xantrex inverter is  Xantrex XW 6048.  Grid interactive but requires 48 volt battery support.

At the end of my previous post, I indicated that I might want to expand my inverter capacity and sell more power to the grid.  The most obvious way to do this would be to buy another Xantrex XW6048 and set it up as a slave to the existing Xantrex XW6048, which would then act as the master.  That would give me 12 kw of selling capability.  The problem with that is that I have had really bad experiences with Xantrex.  My system was installed by a NABCEP-certified installer.  It took eight months to get it to operate even moderately well.  The first inverter would go into power output oscillations, sucking power out of the battery and selling more power to the grid than the PV array was making.  Then the inverter would realize that it was sucking the batteries down, and it would greatly reduce the amount of power it was selling and re-charge the batteries for a while.  Then the whole cycle would start all over again, with a periodicity of about five seconds.  This went on for hours.  The installer spent a lot of time talking to Xantrex technical support, but nothing seemed to work.  So after about a month or two, Xantrex decided to recall that inverter and send a new one.  Took a couple of months more to get the new inverter.  Apparently Xantrex (and  most other inverter manufacturers) are backlogged due to heavy demand.

With a couple of exceptions (explained later), the new inverter worked just fine--for 36 hours.  Then it just completely died.  More discussions between Xantrex and the installer, and Xantrex sent him a test procedure to find the problem.  When he ran the test procedure, it indicated that the main control panel was not working, so Xantrex said they would send a new main control board.  Took almost a month to get it.  I can get wind turbines from China faster than that.

So now, it's working.  Sort of.  The Xantrex charge controller and the Xantrex System Control Panel indicate that the PV array  is putting out 250 watts more power than the inverter panel indicates the inverter is producing.  So, what's happening to the missing 250 watts?  Only the good lord knows.  As far as I can tell it isn't being dissapated anyplace.  Another problem:  there isn't a one-to- one correspondence between the Xantrex owner's manual and the Xantrex equipment.  The equipment has screens and features that aren't explained or even mentioned in the manual, and vice versa.

All in all, my experience has been bad enough that I don't think I want any more Xantrex stuff.  In fact, I got so discouraged, that I went out and bought (from Affordable Solar) an Outback inverter package.  It was all pre-wired and assembled so that all I have to do is hang it on the wall and hook it up to the battery bank, the PV array, the grid tie breaker, and the critical loads subpanel.  It contains two stacked Outback VFX 3648 120 volt inverters hooked up in master-slave configuration to produce 7200 watts at 240 volts, the Outback FX 60 charge controller, Hub, Mate, and Digital Panel.  That Outback system puts out 7200 watts, and if I need to I can stack two more inverters on it and have 14.4 kw output.  I haven't hooked up the Outback yet, but I'm going to soon, and then the Xantrex will just go into the standby mode.

You mentioned that you bought two Exmork 2.5 kw wind turbines; one for spare parts.  I don't see much that could break and need parts, other than the alternator bearings.  I know that Chinese bearings have received a lot of bad press in this forum recently.  I don't have any bad experience with Chinese bearings; but, as a precaution I ordered a spare set of bearings for each of the two turbines sizes (the 2.5 kw and the 5 kw).  Those are the bearings that James Ye said would be free.  My plan is to take enough measurements off those bearings to be able to order an equivalent Timken or SKF bearing.  Besides, it is a corollary to Murphy's law that if you lay in a spare part to fix a part that might break--that part will never break.

The Exmork folks use a mixture of metric and English sized components.  The fasteners are all metric.  On the other hand, they sized the mounting sleeve for 3 inch pipe.  I'm hoping their bearings are sized in English units; on the other hand maybe Timken makes metric sized bearings.  I'll post something if I find a good replacement bearing.  When I do, it'll probably cost half as much as the complete wind turbine.

I wanted to say a little more about feed-in tariffs.  Apparently they are all the rage in Europe, especially Germany.  But they're starting to show up in the U.S. also.  There is a city in Florida that imposed them.  They are revenue neutral to the utility because the utility passes on the cost to its non-power-producing customers.  What a wonderful way to promote RE.  And on a grander scale, to encourage distributed generation, replacing big old coal plants that have to transmit the power they produce over long distances with millions of small generators that produce power just a few miles (or maybe a few hundred yards) from where it is consumed.  Google "feed in tariffs" if you're interested.

poco

[poco dinero]

Hello Cdog,

I can't post a picture--hell I can barely post text.  But I'll try to describe it as best I can.

Look at the picture of the 5 kw machine on the Exmork web site.  That tail boom assembly is about 12 feet long, and the boom is rigidly bolted to the alternator housing.  The prop axis is offset from the yaw axis by a mere 3 1/4 inches.  Notice the huge amount of lead the machine has--the plane of the rotor is 32 inches upwind of the yaw axis.  That keeps furling going, once it starts.

You can't tell from the picture on the web site, but the tail feather is 1/8 inch thick steel and it is one piece.  The whole tail feather rotates about that inclined shaft that it rides on, as a single piece of metal.  Under zero wind conditions, the tail hangs vertically because the bottom part  (the part below the inclined shaft)  is much larger and heavier than the smaller top part.  When the machine furls, the boom swings around so that it and the tail feather are no longer downwind, and the wind starts striking the side of the feather.  Since the feather is hinged about that inclined shaft, and the bottom of the feather has more surface area than the top portion, the bottom wins and the entire feather rotates about that inclined shaft, reducing the area of the tail feather that "sees the oncoming wind".  I guess if the wind blew hard enough, the tail feather would rotate enough so that it was practically "edge on" into the oncoming wind.

So here's the way the furling works.  The wind increases until even that small 3 1/4 inch offset causes the rotor to start furling, i.e. rotating about the yaw axis.  As the rotor furls, the fixed tail boom also starts coming around so that the wind starts striking the tail feather from the side.  That causes the tail feather to rotate about that inclined shaft, reducing the effective area of the tail feather, which allows the rotor to furl further, which brings the tail feather more broadly into the wind, etc, etc, until there is a balance between the furling moment generated by the rotor and the unfurling moment generated by the tail boom and tail feather.  I think what Exmork did was to balance the area forward of the yaw axis (rotor and alternator housing) and the area aft of the yaw axis (the area of the tail boom plus the reduced area of the tail feather) so that when exposed to the wind it furls until the rotor is almost edge on to the wind.  That's when maximum furling is in effect.

So assume the wind continues to increase after maximum furling has been achieved.  Furling can no longer control the speed (rpm) of the rotor.  That's when dynamic braking kicks in.  The controller ups the voltage that the alternator has to work against, mopping up the any excess power put out by the fully furled rotor.

I guess it works, I hope it works, they advertise 110 mph survival wind speed.  Remember, I haven't flown this thing yet.  But if I have doubts about the weather or wind strength, remember also that this machine has the ultimate means of shutdown:  a six inch diameter, 2 inch wide drum brake that is activated by a cable from the bottom of the tower.  And since the machine has slip rings, there's no tangling of the pendant and the brake cable.  Hey, what'd ya want for $2050 USD.

The furling on the smaller Exmorks works the same way, although the ones below 3 kw don't have a drum brake.  James Ye says they are just small turbines.

poco

[poco dinero]

Hello TomW,

I want to respond to your comments regarding my post, although I realize that the thread is getting a bit dated, so you might not see my response.  I hope that somebody who is in contact with you will call it to your attention.

The opening paragraph of your post seems to imply that you think I bought a non-listed Chinese inverter.  I didn't.  The Chinese wind turbines that I bought are unlisted, but there's no listing requirement for them, not even in the U.S.  My inverter is a UL-listed Xantrex XW6048, and it is legally grid tied.  I even got an $1830 rebate check from the local utility company.

"This thread seems to have turned into a how great the Chinese equipment is thread.  I hope folks see the other side of the coin as well."

Well, golly, gee, I guess I didn't realize I was excessively pumping the Chinese equipment.  As I stated in my original post, I haven't even flown any of this stuff yet.  How do I know if any of this stuff is any good?  I don't.  I'm taking a chance.  No guts, no glory.  It certainly passes my visual inspection with flying colors.  And the "features/price" ratio beats anything I've stumbled across so far.

I don't have to fly those hydraulic towers to see the inherent quality they project.  The quality jumps right out at you, especially if you've spent your entire professional career working in the mechanical and structural engineering fields, as I have.  Besides, towers are just a dumb, simple structure.  It doesn't take much brainpower to look at a tower and see that it is built strong enough; just a little bit of common sense will do ya.  If you still have doubts, compare the specs for these towers to Skystream tower specs available on the SWWP website.  The foundation bolts are longer and more numerous; the bolt flanges much bigger diameter, etc.

Maybe the negative information on the other side of the coin has to do with hydraulic failures.  I have years of experience with hydraulic systems (mostly on nuclear submarines), and my experience is that hydraulic system failures are mostly, if not entirely, graceful failures rather than catastrophic failures.  An o-ring blows, a hose springs a pinhole leak, that kind of thing.  I have never seen a catastrophic hydraulic failure.

If you have any of that information that is "on the other side of the coin" regarding Exork turbines or the Exmork company, or hydraulic towers, could you please release it to the members of this forum?  It might save them a lot of heartbreak if they had your information, instead of just relying on my experience.  If you don't have any of that information that is on the other side of the coin, then your comment is, and should be taken as, just a thinly-veiled scare tactic.  To what end, I have no idea.

"You are new here so please forgive if some (read I) might get suspicious when they see comments on how great something commercial is from new folks"

Well, excuuuuuuse me.  Yes. that tower post was my first post.  But I've been a reader of the Fieldlines forum for about four years.  I was in the learning mode, now I feel I have something to contribute.  But I'm hardly a newbie.  I bought my first wind turbine in 1982.  (When did you acquire your first wind turbine?)  I have built a Homebrew 10 footer.

Your comment about being "new here" reminds me of a pack of dogs, who, when a new dog shows up, they all sniff his rear end to see if he is OK, or not.

"Poisoned pets. . ."

I don't know what to make of that one.  Did somebody poison your dog?  No Chinaman, and no American for that matter has ever poisoned one of my dogs.  I have four beautiful Australian shepherds.

". . . stolen designs. . ."

Not sure what to make of that one either.  The Exmork furling design is an absolute original, as far as I know.  Nobody else uses it.  Maybe Flux can chime in here since he has such a vast knowledge of the history of the development of small wind turbines.  How about it Flux, or Hugh, have you ever seen the Exmork furling system used by somebody else?

Yes, the Chinese have marketed some defective products, but what's new.  We Americans have also put out lots of trashy products.  Corvairs, thalidomide, asbestos products, PCB transformers, Vioxx, and the USS Thresher (SSN-593) come to mind, but there are a host of others.  Why single out the Chinese?

"We are targeted by SPAM on all levels"

I've never received a spam in my entire life.  Furthermore, what does that have to do with wind turbines?  No comprehende senor.

I think you have betrayed your motto "The Truth is the Truth, etc."

poco

Beware the nattering nabobs of negativity" - Spiro Agnew

[TomW]

poco;

First, I was not responding to you. I was replying to pilot.

Everything I cited is well documented and was also clearly expressed as an opinion. Yours varies. So be it.

Last post to "your" thread from me. I hope you enjoy long life from your high quality Chinese equipment.

Tom

[cdog]

Thanks for the explanation, it actually made sense to me!

I wonder if it is as effective as the method used here?

Thanks again,

Cdog.

[poco dinero]

Hello cdog,

Just a couple of final comments if you're still around.

One good feature, in my opinion, of the Exmork furling system is that there are no hard metal stops for things to slam into.  When it fully furls it should just dance around up there, furling a little bit more, then unfurling a bit, etc.  No hard metal stops.

Another good feature is that the furling is user adjustable.  If you want the machine to run faster before furling, you can increase the angle of that inclined shaft.  There are three bolt holes to adjust the angle.  I'm going to start with the middle hole.  Sort of like increasing or decreasing tail weight on the Otherpower design.

I don't know if it is as effective as the folding tail boom used by Otherpower, Hugh Piggot, and others.  But if the thing truly can survive 110 mph winds (as advertised), then I'd say it must be pretty effective.

I'll post a comprehensive test report in  couple of months when I get these things flying.

I sure wish we could get Flux to comment on this furling system.  He appears to know more about furling than anybody else on this forum.

poco

[poco dinero]

Hello TomW,

You may be through with me,  ("Last post to "your" thread") but I'm not finished with you.

"First I was not responding to you.  I was responding to pilot".

That statement is not true.  Pilot never said anything about "how great the Chinese equipment is".  That comment could only have been directed to me.  Once again, Tom, you betrayed that sanctimonious motto of yours, "The Truth is the Truth, etc., etc.

"Everything I cited is well documented and was also clearly expressed as an opinion"

I asked for your documentation which I assume was the information contained "on the other side of the coin", and you provided nothing.  All of us on this forum might be able to benefit from your documentation and your obviously extensive knowledge and experience with Exmork wind turbines and hydraulic towers.  Please share, or refer us to the place where we can find that documentation.

The word "opinion" never appeared a single time in your response to my post.  Anybody can claim, after the fact, that they were just expressing an opinion.  B.S. walks.

"I hope you enjoy long life from you high quality Chinese equipment".

I doubt that you hope anything of the kind.  The sarcasm in that statement is obvious to the most casual observer.  

I never excessively hyped the Exmork wind turbines as "high quality".  I admitted I haven't flown any of this stuff, and merely stated that the wind turbines certainly passed my visual inspection.  Have you inspected one to determine its quality of design and construction?

Some Chinese products are of high quality.  My favorite weapon in Vietnam was the trusty AK-47, but not just any old AK-47, but the Chinese version, which was far superior to the Russian or Czeck Kalashnikov AKs.  Nothing short of a 50 cal. machine gun barks like an AK-47 on full auto.  Oops, here I am, hyping Chinese products again.

One lesson in life that you apparently never learned, Tom, is that sometimes a guy has to take a few licks like a man, and forget the whining.

And, now that I've aired these thoughts, it wouldn't surprise me if you cut me off from further postings.

poco

[pilot68b]

Poco,

I ordered two 2kw new cast aluminum turbines, with grid tie controllers. James said they no longer sell the 2.5kw. But, like you said the specs are the same. I plan to use an Aurora Inverter for my install.

John