Wind Turbine Testing

[Matt Au]

 

Hi all,

I am new to the board and have been building Wind Turbines for 4 years.

I have a 12volt/2000Ah batt bank and 18Amps of solar.

I use a dual Stator F&P smartdrive setup, with a motor at each end of the shaft.

I use a 2.2M blade rotor and can get about 30-35amps at 10m/s.

I am living in Australia, Melbourne, where there are plenty of these units for free.

Have been building PM car alt`s also, 1.2M blade rotor and 10amps at 10m/s.

I recently built my most efficient Turbine using a 24v truck alt with standard 40Amp stator and big Neo Magnets 25mm/30mm/11.5mm, and along with a 1.5M blade rotor, i am getting over 25Amps at 10m/s and 10Amps at 6m/s.

Spoke to both Dan`s about this and they were very supprised.

I have a good Anemometre/Logger and a very good Reg, Plasmatronics PL-20 which displays Amps/Ahrs and many other things using a 100A shunt to measure current.

Also a 50Amp analog meter with external shunt is also used.

Question: Would like to check that these figures are correct for my new Turbine, as it sounds too good to be true.

What other means apart from vehicle testing would be an acurate way to test the power output in different wind speeds and determine whether the new turbine puts out what i think it does.

If it does, it would be toooo efficient, around 35%-38%.

Matt Au.

[Flux]

Matt

Power curve testing is quite difficult and the only satisfactory method uses wind speeds usually 1 minute average and sorted into bins at 1 mph or M/s intervals. Even then you get rogue readings that you have to discard. It is also influenced by the wind at the time, High winds give over optimistic low end and vice versa so you need many hours of data or you have to do it in sections with the different wind conditions.

Comparing anemometers on a spot basic with power out tends to give very optimistic readings.

I have never tried Vehicle testing but from results I have seen this also seems to give optimistic results.

Your results seem optimistic compared with anything I have achieved.  I can manage about 35% propeller out, then taking the alternator efficiency into account which I doubt is better than 80% in your case you are looking at somewhere near 28% if you match this to best tsr. I doubt you can hold this over much of a speed range and in lower winds your iron cored alternator is going to fall well below 80% as the effect of iron loss becomes greater.

You have obviously got the setup matched quite well and are doing well for a 1.5M prop.  In general I don't think there is much reliable data for you to compare with, at least you will have a fairly good comparison with your own machines.

Flux

[Matt Au]

Thank`s for your quick answer Flux, and yes, much more testing needs to be done.

The data logger i use soughts the wind speed and direction into speed bins etc with .5m/s intervals, which i display on a laptop.

As you noticed i have also been using my 2.2M F&P turbine for comparison, and this new 1.5M turbine is just behind it by a few amps all the way, which is wrong.

Another way i have tested the output was to check the maximum amps (MAXHOLD) with an expensive digital clamp meter and then checking the graph on the laptop soon after.

I have many more things to talk about regarding Turbines but will stop here as i tend to ramble on.

Matt Au.

 

[RP]

Matt,

I'm curious, are your current readings into the 12volt bank or are they at dead short conditions?  The watts out of the systems have to be volts times amps measured at the same time.  I know others here have made the mistake of multiplying open circuit volts times dead short amps.

Hope this helps

[Matt Au]

Hi again,

Yes, I always test the output of the turbine going into the battery and i often use the formula, Volts times Amps to get total Watts and came up with around 13.5V*28A=380watts. I have had this continous for over 30sec intervals, as the wind rarely blows at 10m/s for any more than 1 or 2 minutes.

I also teach wind energy, and as you are all aware, if you short the output of a wind turbine, you will get high amps for a short time then usually it slows down nearly to a stop. I never use this method to measure the turbines output.

I sometimes short the turbines if i know a wild storm is coming, just for safety.

My system has an 18 amp solar array and various sized turbines going into a 12V/2000Ah battery bank, I use a 1000W Inverter which runs our fridge, which is the biggest consumer.

All this is logged with an intelligent Plasmatronics Regulator showing a 30 day history of everything you could think of, eg: Wind Amps & A/hours in battery, Inverter load amps, A/hrs out, S.O.C and solar/wind input individually.

Thanks for your reply,

Matt Au.

[aogden]

Matt,

Could you give more details on your blades? What is the profile? Do you have any photos of the generator or construction sequence?

Thanx, Adrian