Author Topic: 5kw failure  (Read 2162 times)

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bamfords54

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5kw failure
« on: August 07, 2010, 12:12:30 AM »
hey guys, I have a few questions for you. we have an exmork 5kw on a 70' tower that burned out the windings a few months ago. the problem is the supplier will not replace the turbine unless we replace the wire run,which is 300' of 4/0 aluminum.Apparently,the controller on this turbine works by shorting the three phases when it overspeeds or the battery is full. The turbine is a 48 volt.The problem is we would need to put in double 500mcm copper to satisfy the supplier.this turbine is also made in 400 volt.my question is could we use the 400v with a step down transformer,and run 400 volts in to the controller using the transformer either before the rectifier or between the rectifier and the battery's. Has anybody done this or is there any reason it wouldn't work? my boss doesn't want to spend the 10 grand or more for the 500mcm copper so I'm looking for any other options at this point. Thanks

SparWeb

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Re: 5kw failure
« Reply #1 on: August 07, 2010, 12:43:09 AM »
What condition are the blades and tail in?  Presumably the windings burned up in a storm of some sort, and the rest of the system would have been put through its paces.  How did it fare?  Are you using the standard Exmork controller?
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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jeraklidis

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Re: 5kw failure
« Reply #2 on: August 07, 2010, 02:44:33 AM »
No offense but you bought Chinese... with no physical braking system or electric furling system....you assumed a 15ft rotor would shutdown by shorting the phases???... people need to know BUY USA EU or JAPANESE....

You should ask yourself a few good questions like why did it burn out. Run with out load??? check the dump... check the rectifiers if they are burned out?
4/0 is rated for 200 amps personally I'd estimate the wind that day (and take a guess at the speed at 70') and tell that supplier to f himself and give you your money back or a new unit.

Check the site out

http://exmork.com/5kw-wind-turbine.htm

50 m/s survivability

Solar would have been cheaper and easier install than a 70' tower...

http://www.affordable-solar.com/asgpower-5040w-kyocera-solar-home.htm

I'm just saying..... US EU or JAPANESE the rest is BS

jeraklidis

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Re: 5kw failure
« Reply #3 on: August 07, 2010, 02:52:35 AM »
1 more thing 48v DC 300'... was it even charging??? there's got to be huge voltage drop on those lines...

jeraklidis

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Re: 5kw failure
« Reply #4 on: August 07, 2010, 02:58:55 AM »
FRIENDS DON'T LET FRIENDS BUY CHINESE!!!!!!

http://www.awea.org/smallwind/smsyslst.html

sorry I had to say it....

piglet2

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Re: 5kw failure
« Reply #5 on: August 07, 2010, 03:51:32 AM »
How old is this 5kw Exmork?

Nowadays their 5kw windmill seems to have an automatic brake!

http://www.exmork.com/5kw-wind-turbine.htm

Personally, I would try to have the batteries and the controller or at least the controller close to the mill or I would buy the 350v or 400v windmill and use it for heating or as grid-tied.

Exmork has a grid-tie controller and also a water heating controller for their mills.

http://www.exmork.com/wind-turbine-controller-a3.htm

http://exmork.itrademarket.com/1417806/wind-powered-water-heater.htm

And by the way, most  small American, Japanese and European windmills are actually Chinese with a new name, a new power curve and a new price.

sorry I had to say it....
« Last Edit: August 07, 2010, 03:55:26 AM by piglet2 »

Flux

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Re: 5kw failure
« Reply #6 on: August 07, 2010, 04:56:00 AM »
I assume this is stand alone?
The 400v machine with transformers would probably work but you would need suppliers approval.

A better solution may be to put the batteries, controller and inverter in a shed at the foot of the turbine and send the high voltage from the inverter to your point of use.

Flux

poco dinero

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Re: 5kw failure
« Reply #7 on: August 08, 2010, 11:31:54 AM »
Jeraklidis,

I have read most or all of your previous posts, and had gotten the mistaken impression that you were an intelligent person.  Your misguided, erroneous, xenophobic comments regarding Chinese wind turbines indicates otherwise.

Posted on: August 07, 2010, 12:44:33 AMPosted by: jeraklidis

Quote
No offense but you bought Chinese... with no physical braking system or electric furling system....you assumed a 15ft rotor would shutdown by shorting the phases???... people need to know BUY USA EU or JAPANESE....
 
 

You provide no first-hand evidence documenting your comments regarding Chinese products in this and subsequent postings.  Have you ever owned a Chinese wind turbine?

I own an Exmork 5 kw wind turbine, and CONTRARY TO YOUR ASSERTION, it does have a six inch diameter, four inch wide drum brake, which can be activated from the ground.  Exmork even provided a winch with a pawl so that you could set the brake and walk away, leaving the brake activated.

And what in blue blazes are you talking about--"electic furling system"?  Nobody uses an electric furling system.  You must be confusing electric furling with electric yaw control.

Oh, and by the way, the controller for the 5 kw Exmork wind turbine has a warning sign right next to the switch that shorts the phases together (the "kill switch"), saying DO NOT USE THIS SWITCH IF THE TURBINE IS RUNNING.  They want you to use the friction brake to stop it, then set the kill switch to hold it if you have to release the friction brake during servicing.

Besides the 5 kw, I also have two Exmork 2 kw wind turbines that are presently flying on 56 foot, hydraullically-operated Chinese towers.  They've only been flying for six weeks, but both the wind turbines and the towers are operating admirably.  They start up in low winds, are very quiet, and during two thunderstorms I have seen them peg the ammeters on their controllers at above 65 amps at 56 volts, or upwards of 3600 watts.  I don't know why, but they aren't much noisier in  40 knot winds than they are in 15 knot winds.  Very smooth operation, no slamming around in gusty winds.  Since I put them up six weeks ago, they have generated over 450 kwh of electricity.  That offsets the production of about 1000 lbs of greenhouse gasses (2.2 lbs of greenhouse gasses per kwh).  I realize that six weeks is a short test time, but my expectations for these machines is very high.  Unbelievably, these machines only cost $575 apiece.  I couldn't buy the magnets and magnet wire to build them for that price.  You can see why I am incensed by people bad-mouthing Chinese wind turbines with no apparent facts or experience.
 
Posted on: August 07, 2010, 12:58:55 AMPosted by: jeraklidis
 
Quote
FRIENDS DON'T LET FRIENDS BUY CHINESE!!!!!!

http://www.awea.org/smallwind/smsyslst.html

sorry I had to say it....

 

Yeah, I'm sorry you had to say it too, since, again, it's pure BS.  The link you provided promotes Redriven wind turbines and Hummer wind turbines, both of which are made in China.  Apparently that escaped your notice.

Unfortunately, that same site also promotes Cascade Engineering products--which received VERY bad press in this very forum about a month or so ago.  Those are the roof-top mounted, multibladed, ducted-fan, twin-tailed machines you see on TV in the Michigan commercials.

Next time, get your facts straight and hold back the xenophobia.  A wise man once said:  "It is better to remain silent and let everybody think you are a fool, than to open your mouth and remove all doubt".

poco.

TomW

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Re: 5kw failure
« Reply #8 on: August 08, 2010, 11:58:43 AM »
Poco;

OK, we get it you love the Chinese.

Now let it go.

You appear to be a "paid spokesperson" the more you post on them to me.

Tom.

poco dinero

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Re: 5kw failure
« Reply #9 on: August 08, 2010, 12:15:35 PM »
Hello Bamfords,

I used the voltage drop calculator at this link:

     http://nooutage.com/vdrop.htm

to calculate the voltage drop in a 300 foot lead-in wire for your 5 kw wind turbine.  I ran the calculation first for the 4/0 aluminum wire that you used.  It came to 12.8% drop, which is not very acceptable.  I had to assume the wire was not in a conduit, though I suspect it is direct-buried.  I used 142 amps, since although the Exmork 5 kw is RATED at 5 kw in 22 mph winds, it can put out up to 8 kw at 56 volts in higher winds.  That's 142 amps.

Next I ran the calculation assuming that you replace the 4/0 aluminum wire with 500 MCM copper wire.  The improvement wasn't dramatic--it still had a 7% voltage drop.  Of course, most of the time the drop would be much less than that, because most of the time the turbine will only be putting out much lower power levels.  Bottom line is  500 MCM wire probably won't solve your problem.

When I emailed James Ye at Exmork, he told me that 150 feet (which I had proposed) was too long of a lead-in wire for my 5 kw.  Now I see why.

Posted on: August 06, 2010, 10:12:30 PMPosted by: bamfords54

Quote
.Apparently,the controller on this turbine works by shorting the three phases when it overspeeds or the battery is full.

No, I don't believe that's true.  I also have an Exmork 5 kw, and the controller has a warning sign right next to the switch that shorts the phases together (the "kill switch"), saying DO NOT USE THIS SWITCH IF THE TURBINE IS RUNNING.  They want you to use the friction brake to stop it, then set the kill switch to hold it if you have to release the friction brake during servicing.  Speed control above 22 mph winds is accomplished only by yawing, no electrical interaction.  The voltage stays at 56 volts.

When the battery is full, the controller trips relays that send the excess power to the dump load.  If you are grid tied, the batteries will only be full and dump load will only be activated if your inverter is too small to send all the power to the grid, or the grid is down.

If I were you, I would follow Flux's advice and put the wind turbine controller, the dump load, the battery and the inverter at the base of the tower.  Then use the voltage calculator to determine the wire size for the wire down the tower.  Use it again to size the high voltage wire from the inverter to your point of use.  Keep the voltage loss under 2%.

I don't know for sure, but I suspect that your turbine burned up because the controller lost control of the turbine due to the length of that lead in wire.  The controller would have been receiving false information about what was going on in the alternator.

poco

jeraklidis

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Re: 5kw failure
« Reply #10 on: August 08, 2010, 01:59:16 PM »
First cut the xenophobia talk... calling out fake racism is the easiest cop out to discredit an argument when it was CLEAR this has only to do with Chinese goods.

So what you are saying is that China produces top notch quality goods that are manufactured in a earth friendly way? Chinese goods are well known to be shoddy and perform less favorably than the rest of the world. All issues aside kg to performance ratio is still favorable to the US EU and JAPAN.

In regards to the list, I provided some great alternatives BUT I never endorsed any of them.

In regards to the braking issue I never knew the 5kw had a mechanical brake it didn't state it on the page.

I assume you sell exmork...

I stand by my comments...

TomW

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Re: 5kw failure
« Reply #11 on: August 08, 2010, 02:17:52 PM »
OK, I am guilty, myself but.....

Lets keep it topical to the original post.

Thanks.

We have the Pub for this stuff.

Tom

SparWeb

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Re: 5kw failure
« Reply #12 on: August 08, 2010, 02:20:49 PM »
Poco...You appear to be a "paid spokesperson" the more you post on them to me.

I don't think that's fair.  I wouldn't bother to stop you from attacking the "faraway chinese" - though I think that opinion is now out-dated.  People used to say that about Japanese cars, but the best car I have ever owned (and still do) was japanese-made (with many components also made in China).  

It's when you transfer a pro-american bias into an criticizm of a particular person that my hackles go up.  Please cool it.  I don't want my respect for your experience and usual helpful nature to be tarnished by something so abstract as a frustration over global economics.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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SparWeb

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Re: 5kw failure
« Reply #13 on: August 08, 2010, 02:22:50 PM »
Tom, you were posting "mea culpa" just when I was writing my own post.  We can lay it to rest.
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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12AX7

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Re: 5kw failure
« Reply #14 on: August 08, 2010, 05:14:02 PM »
The longer it goes the more it shows.....

this thread belongs in either "Reviews"  or in "the Pub"

ax7

bamfords54

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Re: 5kw failure
« Reply #15 on: August 09, 2010, 08:05:49 AM »
Alright,I see I touched a nerve or two. Just a few more points to make. The exmork was only flying for about two months. It is not mine,it belongs to my boss and wasn't working when I started working here in June.Nobody here knows much about wind power,so I offered to see if I can fix it.We are completely off grid so gridtie isn't an option. Moving the batteries isn't practical either as all the  solar,backup generator,and quad stacked FX inverters are allready in place and wired. One possible option is to move the controller and dump load to the base of the tower,and run DC in to the batteries. The rest of the turbine is still in good shape,just the windings are burned out. Also I have no idea in what wind speed it failed,nobody saw it happen.

Janne

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Re: 5kw failure
« Reply #16 on: August 09, 2010, 08:40:39 AM »
I usually don't bother to reply to this kinds of postings, but i suspect some of the persons mocking exmork haven't actually seen the machine. I agree, usually the chinese turbines are not so good in build quality, but this exmork seems to be an exception. They're guite heavily built compared to their power rating, even their 3kW unit must weigh around 80kg(judging by the effort it took for me and my friend to move it around, before we took it apart.), and that is without the blades and tail!. Also the data they provide about the performance of the machine seems very reasonable, so i'm inclined to believe they're lying a lot less than the usual manufacturers.

The controllers that are shipped with them seem to be the weak point. The couple of guys that are flying exmorks in here have all just dumped the original controllers and are using brand name dump load controllers to protect the battery banks.

I know it's scary that the chinese have started to build better quality too, how can we now argument for the turbines built in western nations? I guess the quality needs to be better if we want to battle the chinese in the long run.
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piglet2

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Re: 5kw failure
« Reply #17 on: August 09, 2010, 09:49:28 AM »
Right.

I am also perfectly certain that they have not seen one.
Or if they have, then they must have other motives.

I just weighed my 2kw exmork, no tail, no hub, no blades, 58.8 kilos.

The complete mill without the tower and the electronics weighs surely about 100 kilos.

And the Chinese, they can make very good whatever when they want to.

Think where all our magnets come from?

By the way, I do not sell Exmorks either, neither do I get money from them.

I have only bought a couple of their windmills and I am very happy with what I have got.

DanB

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Re: 5kw failure
« Reply #18 on: August 10, 2010, 02:35:27 PM »
I suppose it's like anything.

Some of the most 'popular' wind turbines out there are low in quality and high in marketing - doesn't matter where they are made.  Theres plenty of stuff right here in the US, made in the US that's fairly junky in my opinion.  There are lots of chinese wind turbines that are marketed in a misleading way and the product is definitely low quality.  I expect there are some that are just fine.  Wading through it all and sorting the good from the bad is the tricky bit.

My opinion...  at this time, buying any wind turbine is risky - and you'll likely get what you pay for.  From what I have heard, lots of those manufactured in China are pretty low quality and customer service is poor.  Most... probably not all.

Buying a wind turbine...  I would look for something thats been around for a while, that you can get real 3rd party info on (find out if there is good customer service, how reliable the machines are... how happy are their customers) - for Chinese turbines right now, there probably is not a lot of that sort of data.  Given time... there will be more.

Regarding Exmork - I've heard some good and some bad, mostly good though so far.  I have no hands on experience with these though.

I am pretty sure however that no geographic part of the earth, and no race has a monopoly on 'quality'.  China produces some really good stuff and some really bad stuff... so does every other place.  Seems lots of us are just slightly scared at the qty of stuff that's being made in china these days.
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DanG

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Re: 5kw failure
« Reply #19 on: August 10, 2010, 02:51:42 PM »
Sure the Chinese like foreign currency transactions a lot - but they enjoy not getting into trouble with communist watch-dogs if, for example, they ship a thousand units to their own Gobi Desert that immediately fail.

Some places export the lower quality production runs, some places only export their top tier work efforts. I wonder what merchants and buyers well into the interior wilds of China have to say about various products!


B529

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Re: 5kw failure
« Reply #20 on: August 10, 2010, 06:46:07 PM »
I have only bought a couple of their windmills and I am very happy with what I have got.


How long have you had them up? Do you have production/wind speed data? If so, how do the numbers compare to the published output? Tower height? Location? Grid-tied or battery based?


DanB

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Re: 5kw failure
« Reply #21 on: August 11, 2010, 02:22:48 PM »
I have only bought a couple of their windmills and I am very happy with what I have got.


How long have you had them up? Do you have production/wind speed data? If so, how do the numbers compare to the published output? Tower height? Location? Grid-tied or battery based?



Good questions that anybody should be wondering before they buy any wind turbine.  Unfortunately ....  unless you buy a Bergey *(no... they dont pay me to say that)* or a couple of other brands you wont easily find that sort of information.  I've not been impressed with most of the small wind turbine stuff I see from china yet but time will tell.  I do know... this keyboard Im typing on, and my monitor, and my computer, and most of the parts in your car (probably) and all my drill bits (except the big ones), and most of my fridge, and my TV and the DVD player underneath it... and lots of other stuff I use all the time, was made in china and it works fine.

Time will tell...
If I ever figure out what's in the box then maybe I can think outside of it.


dnix71

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Re: 5kw failure
« Reply #23 on: March 29, 2011, 09:36:08 PM »
Instead of cussing at "the foreigners" the Chinese should be encouraged to follow the Japanese business model in the US. Make the parts in China and assemble the product here.

Plenty of 'Japanese' cars made in California, Mississippi, Tennessee and Kentucky.

Open a factory and employe Americans. Assembly here means spare parts and a someone who speaks English to offer tech help and assist in warranty claims.

And follow the business model that MacArthur taught them after the War. Make a product well and don't worry so much about the price. After the word gets out that you make things well you will have plenty of business and can name your price.

I wish the Chinese success. More renewable energy means a saner, safer world.

Madscientist267

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Re: 5kw failure
« Reply #24 on: March 30, 2011, 12:11:48 AM »
It will never happen.

Too expensive.

That's why things are the way they are now. I'm no "xenophobe" (I had to actually look that up), and could really care less about what is made where by who, but I can tell you that the business models between Japan and China are radically different animals, and if there is a trend in any direction, it would be the Japanese following in the footsteps of the Chinese.

Case in point? Sony. I have an antique reel to reel that was bought second hand, before my siblings died on the sheets, and the only thing wrong with it today is that the volume pots are worn completely out. They can be made to work long enough to demonstrate that the rest of the unit functions just fine. Its had a couple sets of tubes replaced. Normal.

Sony VIAO? POS. Way over priced, flimsy components, and God help you if you need to ever replace the DC power jack; that little piece of crap plastic part with 2 wires dangling from it will cost you over a hundred bucks, and that's before you get suckered into having someone install it for you. No thanks.

I used to sing the praises of Sony, then I repaired a bunch of customers laptops, and learned the new age truth about this little "gem" that is no more. The Japanese morality model was "work before family", which I didn't necessarily agree with completely, but it was better than their new motto:

"Screw it, the Chinese are doing it!"

Rant over.

Steve
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How much magic smoke it contains does !

Antero

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Re: 5kw failure
« Reply #25 on: March 31, 2011, 12:03:13 PM »
I agree 100%.

You have in America products of millions and they are massproduced and cheap.
So have we, here in Europe.

Why an earth, we must import windgenerators to western world ?
They are in nowadays technical know how, very simple machines and could be easily massproduced.

I think its just a question of choice  ;)

You, who are building windgenerators DIY, are pioneers in this.
When there is enough "critical mass" it starts the real movement and production of windgenerators.

Antero Rantanen
Finland

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Re: 5kw failure
« Reply #26 on: May 30, 2011, 09:29:18 PM »
We Americans need to get over it, our century is over, we are destined to become the same foot note the French and Brits are on the wold stage are now, the Chinese will be the next and only world superpower within twenty years, we will be bankrupt with our rusting hulk super carriers being broken down and scrapped in Chinese scrap yards, the next century will be the Asian century, our time in the spot light is over, so get used to it, it is inevitable it cannot be changed or stopped anymore.
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