Imitation "Skystream" Project.

[Andy Rhody]

After getting the "Wind Bug" and a few years of making Ametec type micro windmills, I wanted to go grid-tie. My goal was to imitate the world's most popular "plug and play" windmill kit, the 2000 watt Southwest WindPower "Skystream" at a much lower cost so last August I pulled the "trigger" on a 2000 watt Chinese windmill for 900 USD and then scored a 2000 watt Ginlong inverter both from ebay. After 13 months I finally got it up at about a little less that half the cost of the "Skystream" but what a journey. I knew so little and if it wasn't for running into Rob Beckers and Larry Leamy, it never would have happened. Thanks guys.

Anyway, first of all, the Ginlong's voltage range is 30 volts to 750 volts and since my windmill was 72 volts, I figured that it was quite within the range. Aparently it doesn't work that way. 72 volts into 2000 watts equals around 27 amps and the Ginlong is only rated at 9 amps. I emailed Ginlong and they confirmed that the windmill's voltage was not high enough for their inverter and suggested that it was made to charge batteries so right away I was stuck. 72 volts is really too low a voltage for most grid-tie inverters but Rob did some math and figured out a way to make the Aurora inverter work. Although the Aurora only goes up to 20 amps, Rob said that we could maybe do a few tricks like cheat on the MPPT curve or in other words, run the RPMs up to 30% higher increasing the voltage and in essence, keeping the amps down. WOW!

Okay, now I needed a controller to rectify the 3 phase AC from the turbine and switch on the dump load. Rob had 2 diagrams from the Solacity web page. We used the one on the right because it uses a single dump load. Check it out.


http://www.solacity.com/Docs/Wind%20Turbine%20Overvoltage%20Protection.pdf

Larry has an electrical company in Eastern Pa. and also installs solar and wind. I showed him the controller diagram and he said, "Yeah, I can build that. I'll show you where to buy the stuff online and then have it all sent to my house". Larry added some more "bells and whistles" like a lighting arrester, fuse and some meters. Here's what it looks like.

http://i41.photobucket.com/albums/e295/andy47bottles/Science/024.jpg

Now the dump load. Remember, I'm trying to do everything on the cheap. When talking to Rob he mentioned heaters and I said that we had a 1500 watt electric oil filled heater that we got at Walmart and he said that that could be a possibility. I went to the Walmart webpage, found one, downloaded the specs and sent them to Rob. After doing some math he said that he thought it could probably work but that I'd need 2 of them to make 3000 watts and that they needed to be wired in series. So, I bought 2 for 35 bucks apiece, gutted out all the controls and hooked them to a junction box in series and the electrical inspector never said nothing. Maybe he didn't even know what they were.

http://i41.photobucket.com/albums/e295/andy47bottles/Science/042.jpg

The pole is the weakest part of my system because it's only 24 feet high. The reason is that I wanted a mono pole and 24 feet is the highest I could get built locally. The guy who made it insisted on me getting an engineer to design it for liability reasons. That cost me 450 bucks US. I know that it's not high enough but we'll see wht we get.

The balancing of the blades. This was tough. Took months. The owner's manual said that all 3 blades were all exactly the same weight so to balance them, just make sure that you have the exact same distance from tip to tip and that they will be balanced. Normally 3 blades should be 120% apart but the bolt holes in the blades were pretty "sloppy" so you could change that a lot. I took them to the local hardware store and weighed all 3 and they varied by a half pound so I knew that wasn't going to work. We even tried a tire balancer but got the best results by hanging the hub from a string (rope). We would adjust the distances between the blades and then measure the distance from each blade to the floor using the same spot on the floor in case the floor wasn't perfectly level. The owner's manual way had a difference of 17 inches or so. We would get it within 3/4 of and inch but then the next day it might change to an 1 1/2 inch difference when nobody even touched it. Drove us crazy. We settled for that and then I made a guide to make it easier to get it right when we were up in the air. It "hooks" on to one blade tip and has a mark to set the other. Check it out. When I put my hand on the pole and feel for vibrations, they seem to be running pretty smooth.


http://i41.photobucket.com/albums/e295/andy47bottles/Science/025.jpg

http://i41.photobucket.com/albums/e295/andy47bottles/Science/026-1.jpg

http://i41.photobucket.com/albums/e295/andy47bottles/Science/027.jpg


http://i41.photobucket.com/albums/e295/andy47bottles/Science/024-1.jpg

http://i41.photobucket.com/albums/e295/andy47bottles/Science/003-2.jpg

So yesterday I passed my last inspection ( that's another story), made a few kw's and I'm "waiting for wind". So far so good.

[Dave Turpin]

So you ended up not using the Ginlong inverter?

I guess the options were to use an inverter matched to the output of the turbine or re-wire the PMA for higher voltage.

[Andy Rhody]

So you ended up not using the Ginlong inverter?

I guess the options were to use an inverter matched to the output of the turbine or re-wire the PMA for higher voltage.

That's correct. I'm not using the Ginlong. I'm using the Aurora 3 k wind. The Ginlong ended up being a dead end street and I'll need to unload it. I could nerver re-wire the PMA. I can't even figure how to get it apart.

Here's a photo of the set-up I was trying to use to make a graph of the open and loaded voltages. The PMA was too big to successfully turn with a hand drill so I tried to turn it with my bicycle. It was tough but I got some crude readings.


http://i41.photobucket.com/albums/e295/andy47bottles/Science/Dads94th003_zpsd9b6b84a.jpg

[Rob Beckers]

Andy, did you get any good wind (storm) yet? I'm just wondering how the turbine behaves with the MPPT curve as loaded, in real wind.

System is looking good!:)

-RoB-

[Andy Rhody]

Thanks Rob, I know that I'm a "ginny pig" with this project but so far everything seems to be working. No big storms yet. We have had days with 15 MPH winds and I did record 1500 watts peak one day on the inverter. Usually when we get good wind, I'm at work. So frustrating. When I first put the turbine up, the utility company hadn't completed their end so I ran it on the dump load and it was furling quite often. Now that the inverter is online, it seems to be furling less which is good. I guess that the load is just different but I'm still concerned that it may be furling too earily. Espically if it furls below a 20 MPH wind. Wish I could quit my day job, buy some beer and hang out all day at the house all day.

On the stray voltage issue, Radio Shack does have a 100K resistor but only at 1/4 watt and I need one at 5 watts so I ordered a couple online at Mouser Electronics so I should be able to fix that quirk this week. At least things are winding down.

[Rob Beckers]

You hit the nail on head about the difference between solar PV and wind: Pulling up the lawn chair and the six-pack to stare at the solar array... Eh, not so much...

Staring at the wind turbine with a beer in hand, while contemplating the finer things in life is a great way to pass the time! :rockon:

-RoB-

[Andy Rhody]

Okay, the 100 K resistor is now installed accross the inverter's DC input and it's shutting down like it should. That was an easy fix.

Still only moderate wind but of course we'll all be getting that hurricane next week and they're predicting 70 MPH winds here in Central Pa. I hope I'll still be in business. "Batten down the hatches".

[Rob Beckers]

Same hurricane is heading this way as well (though a tropical storm by the time it gets here). It's pretty rare for them to come through here, we'll see how that goes. Andy, this should be your chance to see what the turbine is capable of!

-RoB-