How does everyone deal with ice on you blades?

[Andy Rhody]

It said in my Chinese windmill owner's manual, (in broken English), " Ice on blade may cause balance problem. Remove ice from blade". Well that's easier said than done.

Ice and snow can cause 2 problems. Besides throwing the blade out of balance, it changes the aerodynamic shape like ice on an airplane wing which can stop the wing from lifting.

So 3 days ago we were having 20 MPH wind and my peak watts only reached 138 watts. The blade was turning slowly and the mill would wiggle a bit with the rotation. Then the next day we got a little sun and things improved but I could still see some ice. Now it's running fairly normal again but hasn't stopped for 2 days so I can't tell of all the ice is gone. It kind'a fixed itself but that was luck.

Anyone ever deal with this?

[John Szegda]

Andy,

My experience with surface icing was when I operated airplanes as a commercial pilot. We used deicing boots on airframe leading edge and trailing edge on props. When ice formed, we activated a pneumatic system that would crack and dispose the ice. We also sprayed Glycol on the surface to retard ice build up during flight. Before I mounted my blades, I gave them a coat of high gloss epoxy paint. That helped with ice formation.

How did your Over voltage/Dump Load Controller work. I'm building one as a backup to my Chinese controller.

John

[Chris Olson]

I typically don't do anything with the ice except leave it on there, and leave the turbine running. Eventually it'll toss it off or it will sublime and just disappear.
--
Chris

[John Szegda]

Chris,

I like your simple approach to the problem.

What type of overvoltage controller are you using with your turbine.

John

[Andy Rhody]

I typically don't do anything with the ice except leave it on there, and leave the turbine running. Eventually it'll toss it off or it will sublime and just disappear.
--
Chris

Yeah, I was thinking that maybe the ice weight on each of the 3 blades might be almost equally distributed so the balance might not be so bad and if the airfoil is incorrect and the blade won't turn, I just wait it out.

Anyway, the mill hasn't stopped for 4 days so I can't check out the ice on the blades but it's running pretty smooth and we're makin watts so I'll just keep watching.

[Andy Rhody]

Chris,

I like your simple approach to the problem.

What type of overvoltage controller are you using with your turbine.

John

I bought the windmill with no controller so we used Rob's diagram from the Solacity web page. We used the diagram on the right which retifies the 3 phase AC through a rectifier which means that you only would need 1 dump load device as opposed to using 3 separate dump load devices for the 3 phase AC.

Here's a photo. The Omron relay in the upper left is the heart of the system.

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

[Ralph Day]

Usually if there's ice built up on the blades of my 1kw H80 it has stopped turning, or is turning very slowly. I just brake it or manually divert to stop it and wait for the sun to melt the ice off. That's really the only option. Even if you could tilt your tower down, do you really want to scrape the airfoil surface to get the ice off for just a little bit of potential power you will miss?

Mind you, I go out and sweep my pv's for just that reason:blink1:

Ralph

[Chris Olson]

What type of overvoltage controller are you using with your turbine.

Just three-phase clippers controlled by the Classics.


Yeah, I was thinking that maybe the ice weight on each of the 3 blades might be almost equally distributed so the balance might not be so bad and if the airfoil is incorrect and the blade won't turn, I just wait it out.

As long as the turbine is running I've never had problems with uneven ice buildup. They'll sometimes shake a little if it tosses ice off one blade and not the others. But I've never seen it last very long because when the ice comes off one blade it's coming off the other ones too.
--
Chris

[John Szegda]

I bought the windmill with no controller so we used Rob's diagram from the Solacity web page. We used the diagram on the right which retifies the 3 phase AC through a rectifier which means that you only would need 1 dump load device as opposed to using 3 separate dump load devices for the 3 phase AC.

Here's a photo. The Omron relay in the upper left is the heart of the system.

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

How is the controller functioning under high wind conditions.

[Andy Rhody]

The controller seems to function just fine. The windmill that I bought was designed to charge batteries so it was difficult to figure out how to make it work with "grid-tie". Rob got it all figured out. The 2000 watt "72 volt" windmill hits 2KW at about 138 volts DC. The Omron Rely can be set from 0 to 600 volts so we have it set at about 27%.

The only time that it ever went into "dump load" mode was during Hurricane Sandy when it peaked over 3000 watts but everything worked as we expected.

Here's my story:



http://www.greenpowertalk.org/showthread.php?t=16847

Okay Chris, if most people don't worry about ice and snow on the blades, I won't either. One less thing to worry about.

[John Szegda]

Andy,

That is exactly what I'm trying to put together now. My problem is with the contactor wiring. Is there any way you could sketch the numeric sequence for the contactor. After testing my unit during light winds, it did not perform to well. Also, what is the fuse protecting and what is the amperage.

John

[Andy Rhody]

Thanks John, See if you can open this file. When Sandy hit the system was dumping into the dump load but clicking back and forth about twice a second. The problem was that we had one wire connected wrong. I drew out everything the best I could and sent this diagram to Rob. The wrong part which is in this diagram was that the V3 post of the omron was connected to the turbine recitifer. The V3 post should go to one of the 3 three phases coming from the turbine. Other that that everything else should be correct if you can read my scribble.

1058

[Cor van Houtum]

Hello Andy,
nice work.

I have introduced the Omron relays a couple of years ago on this website
but in the mean time i was looking for a more easy way of controll

I have tested a other kind of relays and I think this combination is even more easy.
the relays is a volt measurement meter with two trigger points
it is easy to program with the buttons.
I like it , and I think this is the next step forward to make the system more flexible.
with this relays you have volt measurement and trigger in one relays
also hysteris is build in.

look at it and give your opinion.
kind regards

Cor

http://www.conrad.com/Enda-EPV141-R-230-SW-Programmable-LED-voltmeter-EPV141-R-±500-V/AC/DC-Assembly-dimensions-70-x-29-mm.htm?websale7=conrad-int&pi=124172

[Andy Rhody]

Cor Said:

Hello Andy,
nice work.


Thank you but the work was done by Larry Leamy of Leamy Electric in Eastern Pa.

That devise looks to me to be a digital version of the analog Omron relay. Have you or anyone you know every tried using it?

[John Szegda]

Andy,

Thank you very much for your time and the diagram. The sketch is good and legible. You mention the only change is the wire between Omron V3 contact and one phase of the Turbine Rectifier. From what I see on the diagram, that lead is already connected to the rectifier. Can you tell me what the fuse amperage is.

John

[Shaun Burgess]

hi cor .. i have to build a controller shortly . ilike the look of the enda epv . is it reliable .does it have to be reset every time there is a grid fail . can the hysteris be ajusted like the omron . i like the read out saves using a volt meter.. its a bit cheaper then the omron . thanks sb

[Rob Beckers]

Andy, regarding ice on the blades: Our official advise for the Scirocco turbines we sell is to ignore it. As Chris mentions, once ice builds up the airfoil is spoiled and the turbine will usually not turn much (if at all), so uneven build-up is not a big deal, if it happens. When it starts shedding it will melt off all blades in quick succession.

This doesn't really add anything to what others said, just another opinion confirming the above.

What does help to shed the ice more quickly is to have black blades. The sun will warm up the blade much quicker (and at a lower outside temperature) vs. white blades.

-RoB-

[John Szegda]

Rob,

You are correct about the black paint. In aviation, most props sold in cold climates are painted black made by a Company called Hartzell.

John

[Chris Olson]

All my Canadian turbines got black blades. But I attribute that to the fact that the first one that ever went to Ontario had black blades. The other off-grid neighbors that seen that my first Canadian customer had his place lit up like Las Vegas at Christmas time that first winter got jealous and they all wanted the same thing. And they figured them black blades must be the ticket because that's what every one of 'em has wanted.
--
Chris

[Jim Erdman]

I've always had 3 bladed wind turbines, since 1977, and never have had any problems due to icing of the blades. If the rotor is left to rotate, the ice will build fairly evenly and has always dropped off when the sun came out or if the wind picked up a little bit. Never noticed any problem with ice being thrown any distance or causing imbalance for more than a few rotations of the blades.

Jim, in Western Wisconsin

[Tom Hoffer]

We had an Ice storm yesterday leaving about a quarter inch of ice on everything and a little more on my spinning 17.5KW Jacobs Turbine blades. Working in my machine shop about 50 feet from the turbine I heard a clunk on the roof. Looked out the window to see my turbine shaking violently back and forth at least 3 feet at the top. The blades were obviously way out of balance and running at a frequency that the tower really wanted to swing with.
I thought the thing was coming down. Had to make a nervous run to the brake to save the old girl. I did an inspection this morning on the tower, turbine, blades, tail etc.. All appears well and is now making power. I'm again impressed by the Jacobs Turbine and Rohn tower combination.
I'm thinking in any moderate to severe ice storm especially if it is also windy, I'll be braking my Turbine.

Thanks Tom Hoffer