Wind Turbines

Same as many other DIYers interested in AE, I have watched the development of wind power for more than 30 years. In my opinion there are two markets here, the big boys, and commercial ventures is an interesting study, and what soon becomes apparent is the challenge to build one of these big machines that will produce a return on investment is a BIG undertaking. It becomes obvious that these machines rely on bleeding edge technologies to take the incredible stress loads and to handle all the dynamic loading presented by the wind. Dynamic braking, handling storms and gusts have created challenges equal to designing materials for advanced fighter aircraft and space vehicles, and sometimes we see the same Engineers working to resolve wind turbine design problems. If you have been following this technology at all, you will know about failures, the loss of turbine blades, towers being ripped from their anchors, gear boxes exploding, braking systems failing, maintenance people trying to save machines from destruction and giving up their lives doing so. There’s lots of money spent here, and the designs are getting good… finally..

There is another market, and that is small and under funded according to my measure. Long ago, there were a number of wind turbines sold by some larger American Companies, RCA comes to mind, and their wind charger was often packaged with a tube radio that ran off batteries. these units were found everywhere across North America prior to the REA bringing electricity to rural areas. When remote Farms and Ranches got their end of the grid, these wind chargers were abandoned, you can still see the remains of these primitive but reliable systems at many ranches, some still standing, others in pieces on the Ranch’s metal scrap pile.

Over the years, we have seen an advancement in machines designed for single family homes and smaller installations. Some of these machines are well designed, and others are simply Junk made to sell. There are a few who sell wind turbines that have zero hands on experience, or even a basic understanding of the engineering challenges these machines must meet in order to survive and/or make you a return on your investment. It is VERY easy to throw your money away, and I’d guess that 90% of the people who see any return invested a lot of hours of research BEFORE making a purchase.

One of the basic mistakes people make is paying too much attention to numbers advertised. Power numbers are often advertised at ridiculous wind speeds you’ll never see and lots of people are just too optimistic about wind. One of the basic premises of investing in wind is the evaluation of the specific site. You can find information about wind in your area on the internet, but this can be misleading as there are all kinds of things that local geography can do to that wind potential, and you may be in a good area according to some map and still have ZERO chance to make a return on investment.

Another basic mistake people make is buying a wind machine that is designed to run at high RPM, some of these machines can sound like chain saws or weed eaters running, and there are a few machines that have been taken off their perches by neighbors who simply have had enough of the noise. If you don’t take these things into consideration before you send off your money, you may find your life threatened at some point. I remember listening to a conversation between two guys having a beer a a Marina in Washington state, a guest boat pulled into a slip near them and let their wind charger run all night, one of them was talking about the line that was thrown into the prop, and how the act had restored the peace and quiet to the moorage.

I just returned from Easton, my wife had strung some ‘tape’ on steel fence posts on our property line. Two weeks later, the neighbor commented that watching this tape flutter in the wind was so annoying they couldn’t focus on the TV next to the window. I took the complaint serious, and I added a post between posts in the area of complaint. I also told the neighbor I’d have no problem putting in a post every foot if that’s what it took to remedy the problem I had created. With this said.. that same window will view my prime location for the tower and wind turbine about 800 feet away. I will certainly process this, and discuss the placement of the wind turbine with this neighbor whether I have a legal obligation to do so or not, why not attempt to work it out up front?

If you have good wind with a mean speed of 15MPH, it may be far smarter to fly a 500 watt machine designed for this speed than a 3KW machine that is designed to run at 28MPH. It’s not about potential, it’s all about the work done over time. You may be pumping this energy into a battery, or might be using a net metering device and the grid for your ‘battery’ or storage device, whatever that is, it’s all about getting a Kwh of energy into that battery regardless of the power rating of the machine.

Following is one wind machine I will likely install at our off grid site at Easton, I purchased it to gain some hands on experience, so many of us understand, when the hands are on the product, that’s when the learning really starts.

Here’s a picture of the Wind Turbine Generator, that shaft is 1.6 inches in diameter near the case, and it’s a tapered and keyed where it receives the Hub for the three blades with a diameter of 8 feet two inches. This machine is rated at 500 watts, and the Gen head weighs 66 pounds, if you look at some of the offering on the internet, they will weight a fraction of this, and they will advertise far higher output figures, it will be your job to figure out what is designed to sell, and what is useful.

The generator section is only the beginning, what are the blades made out of? Will they hold up to the weather and to the speeds your system will see?

Here’s a picture of the Wind Turbine Blades, this topic could be a book all by itself and barely cover the basics. A strong well designed hub and blades that are strong and efficient to extract that energy from the wind and transfer it to the generator shaft are basic. we might add balance of the rotating assembly, as this is key to longevity and efficiency.

There are many products designed by Engineers that have no practical experience look here for a few examples. There are also a lot of companies that totally discount experience, many of these decisions are made by people with zero mechanical or electrical ability or training. For them, they think, “just how hard can it be?” and they know that a kid right out of school is cheaper in wages and total compensation. With that said, here’s a picture of a controller sub component used for a wind turbine like the one pictured above.

Here’s a picture of the dump load resistor located in the bottom of the controller. This is a rather large resistor, and it is designed to put a load on the turbine generator and keep it out of over speed. Note the Fan in the back ground, and note how the wires are routed through the sheet metal.

The DIYer/AE enthusiast will look at this and ask himself, why would anyone put the load resistor in the bottom of the case where all the dissipated heat can cook the electronic above? Next Question is… what happens when that cheap fan fails and we have no cooling? Another question, what temperature will that insulation on the wires going to the dump load resistor take? Yet another question, why did they route the wires thru the sheet metal with no grommet, and why together? So we ask ourselves, what happens IF we lose that fan AND we have high winds? The answer could be we turn this controller to a molten piece of hot plastic and metal followed by an open between the turbine output leads and the dump load. This could be followed by the loss of a turbine blade or a portion of the blade, the large imbalance, and the total destruction of the turbine generator, blades, and hub as it smacks the ground. When it hits, even that large and impressive shaft may bend!

As I examine this controller, I find some excellent work, The wire connectors are of excellent quality, lots of heat shrink in use, efforts to route wiring neatly, and more.

I note that the rather large transformer in the inverter section is held in with two screws on one side, and the other two screws are missing, there is also a grounding lead that was supposed to be tied to one of these missing screws. Products read like a book, there’s a QC passed sticker on the assembly. These are signs or a rather new product and low production numbers. This transformer is heavy, and it needs all those screws!

One of the biggest problems I see with this product is they stuff three products into one box. I think the inexperienced design team thought they were doing something wonderful for all humanity, a sine wave inverter, a controller for both the wind machine and optional solar panels all in one box! but wait, there’s still more, there’s that clever dump load right in the same box!

I don’t yet know what the power required to keep the inverter on line is at no load, but I bet it isn’t impressive.

My direction is to design a dump load that needs no fan, hey that’s easy, and we’ll even consider making use of the heat. There’s of the shelf controllers that will handle the task.

Stay tuned, this story will likely evolve as I add wind power to my existing off grid AE power system at Easton. Maybe my neighbors and how they react to wind power will be part of the story? Now to process the tower requirement, the loads, the placement. So many things I need to learn and understand BEFORE I continue. I am always a student, maybe you can learn from my mistakes? I’m sure I’ll make them.

All the Best,

George