Author Topic: Todays wind tunnel test. (Read 2938 times)

Jerry · « **on:** July 06, 2009, 12:55:32 AM »

I made 2 upgrades. 1st I added a digital amp meter (more accurate amp reading, 2nd I installed a belt between the 2 drive motors. Now all 4 fan blades are spinning at the same RPM.

I had just enough time to test the Garbogen and the GE-ECM.

Here are the Hughs 4 FT, and the 14-11 test #s from my previus tests and the 2 machines fron today.

Hughs 4ft 22.86 watts at 14 mph.

14-11 4ft 32.18 watts at 14 mph.

GE-ECM 4ft 37.73 watts at 13 mph

Garbogen 4ft 44.64 watts at 13.5 mph.

I also tested a 2.5 HP, 2250 rpm, 19 amp, 130 volt tred mill motor. It was about the same as the GE-ECM.

I tested the GE-ECM at 24 volts. I need to reconfigure its wireing for 12 volt testing.

The Garbogen also had the earlyest cut in.

I still need to test Hughs alt with his sugjested wood carved blades. This may change his #s greatly?

I'll try to test my small 8" dual rotor 12-9 "Jerry Rigged" tommorow. Its also a 24 volt unit.

I'll post more #s ASAP.

Jerry

imsmooth · « **Reply #1 on:** July 05, 2009, 07:11:23 PM »

That's like a 30-35% efficiency for the Garbogen. How did you get the efficiency so high?

Jerry · « **Reply #2 on:** July 05, 2009, 08:25:02 PM »

Hi Jonathan.

I've been building the Garbogen a long time. I've allways thought it was a good small machine.

However I've also thought its never had much intrest or respect?

Its a very simple machine. 4 very powerfull curved NEOs within 1/32" inch of the steel laminet stator wound with a 10 amp 30 volt coil. This is 1 coil of 4. These are the run windings. After perelleling all 8 coils the amperage goes up. 4 starts seperate from 4 runs rectified seperatly. Its acttuly a 2 phase pma.

There are also 4 start coils good for 5 amps each. This is a total of 60 amps worth of coils. I've acctully pushed the Garbogen over 80 amps. The magnetic flux is much like that of a transformer?

I cuts in around 550 rpm. It has some cogging but at 10 mph the 4ft blade will break it loose for startup and cutin is 6.3 MPH.

I did some bench testing in my diary here. http://www..fieldlines.com/story/2008/11/19/213549/76 This test showed a slightly higher efficiency of the Garbogen over Hughs machine on the bench also.

It way out preforms the SW AIR-403 the Hornet and such and with no noise.

And yet people still buy those machines???

Jerry

dnix71 · « **Reply #3 on:** July 05, 2009, 09:33:51 PM »

http://www.fieldlines.com/story/2008/11/19/213549/76

is the correct Diary link. There is one too many dots (www..fieldlines) in the link above.

gizmo · « **Reply #4 on:** July 05, 2009, 09:44:41 PM »

Good work Jerry.

You cant beat this sort of testing to get the facts on different alternator configurations. While all the theory might say this alternator type is better than that alternator type, its not until you actually compare them in a real live test that you see the full story. Maybe, just maybe, a converted induction motor, with all those horrid iron losses, is more efficient than a axial flux alternator. At least for a 4 foot turbine diameter anyway.

I'll watch your results with interrest.

Glenn

oztules · « **Reply #5 on:** July 06, 2009, 02:17:54 AM »

Yes, interesting testing from Jerry again. Gizmo, I'm not sure your walking away with the right interperation of the data.

It shows us how each unit performed with Those blades at That wind speed with that Battery configuration with that load matching... nothing more and nothing less.

Load matching is infinately more important than anything else.

It is inconcievable that an ideally matched unit with iron could get more out of a given wind, than an axial ideally matched at the same wind speed..... one has an anchor towed out the back, and one does not.

If we had a true MPPT (not the midnight unit with jump table style matching...(much better than none at all) but true mppt), then this test may be useful to compare the different types, as the load matching will be assured, and so the alt losses will be the deciding factor.

A simple example... my 4m axial can deliver over 1kw easily in moderate winds@48v nominal.... Connected to a 24v bank, it will never get more than a hundred odd watts (stalls).... same alt, same kind of winds... 1000% different result.... but at very low wind speeds the 24v unit can charge something... before the 48v configuration achieves cutin. At this speed, the 24v unit is infinately better.... damn windmills.

With wind, the matching is everything.

This would be a terrific test bed to make changes to a given set up to achieve the optimum output from a particular unit in 14mph winds.... a very useful tool indeed.

Without optimising each one, it is difficult to compare type vs type. (eg at 4mph, the axial will produce something, the cogging iron core nothing ... an infinite increase? At higher winds, the axial may be designed for stall operation, and so the iron core with some inductive reactance may let the blades follow the TSR better and extract more.... until the reactance limits it........ and on it goes.

Well done Jerry... but I'm not completly sure what it really proves.....but I like it none the less.

..........oztules

gizmo · « **Reply #6 on:** July 06, 2009, 07:12:38 AM »

I knew I would get a bite

imsmooth · « **Reply #7 on:** July 06, 2009, 07:18:06 AM »

Without having a MPPT inverter, maybe the data would be more useful then if various wind speeds were tracked. One could then get efficiencies from low to high wind speeds instead of point data.

electrak · « **Reply #8 on:** July 06, 2009, 07:58:21 AM »

If I recall, you run your fans though a autotransformer, so you can adjust speeds, the 14mph is max. Can you get a tach for blade rpm? how about a largish reostat into a short? adjust for manual mppt and check volts and amps?

Jerry · « **Reply #9 on:** July 06, 2009, 08:58:13 AM »

Thanks for all the input guys.

I'm not convinced the AC motor conversion is the best either. I'll be testing my small duel rotor 8" machine.

Keep in mind Hughs 4 ft is a single rotor. I think this has some influence on its eficiency?

I think he purpessly designed it as a single rotor to acomidate the 4ft blade?

I recall my 8" duel rotor out preformed the Garbogen? We'll see, I'll be testing it also.

I've got a set of carved wood blades now to test on Hughs alt. There again we'll see?

Much more testing to be done. Its too early to come to any big conclusions.

I'm just testing and reporting the findings.

Thanks for following along and all the thoughts.

Jerry

Dave B · « **Reply #10 on:** July 06, 2009, 10:01:28 AM »

Great work Jerry, you knew there would be controversy and misinterpretation of your reporting. I give you great credit for doing what very few (if any) have done here in this board. Now the "what ifs" "shoulda, couldas" "I would have done it this way" or "why didn't you do it that way ?" statements will come in from all over. You are reporting on your findings for the set up that you have created, this is great work. Those quick to jump at it sometimes miss the point. Super job, Dave B.

Stonebrain · « **Reply #11 on:** July 06, 2009, 10:04:12 AM »

Or,with a different loads (I think for this you need a resistor bank instead of a battery) at the same windspeed.

stonebrain

ghurd · « **Reply #12 on:** July 06, 2009, 10:22:47 AM »

Did you get something in there to deal with the turbulence?

G-

Jerry · « **Reply #13 on:** July 06, 2009, 08:18:02 PM »

Hi G. No havn't done any of the turbulance straightner stuff yet.

Stone brain I do have a good colection of high wattage resistors to load with.

Do you have a value in mind? I just figured these wind generators are typicly used to charge batteries and Im trying figure wich unit does that best.

I tryed the 4 FT carve wood blades today. I was very disapointed.

These are not the official Hugh Piggot wood blade but very simular.

I could not get enough wind speed to start them turning. I had to give them a hand push to get them started. This was at 15 mph.

Once spining they maxed out at 2.8 amps. The plastic "Jerry Blades" started up by 10 mph and did over 4 amps at 15 mph on the same genny.

I hope the Hugh blades do better.

I hope to test the Hornet tommorow. I've got there 6 blade set up and one of there older GM alts with the NEO doughnut magnet.

I'll test it all stock, star and there blades. Then I'll test it with a fullwave bridge and cap per phase. The 3 seperate DC outputs will then be wired in sires.

This was the best coinfiguration I found during bench testing. Check my diary for that one.

The alt is basicly the same as Wind Blues. However Wind Blue uses the TLG blades from Terry.

I'll be trying my 4 ft blade. So both blades sets and both wireing scheems.

Jerry

willib · « **Reply #14 on:** July 06, 2009, 11:03:48 PM »

Hi Jerry,

I'm looking forward to your test results.

Congrats on your wind tunnel.

It sounds like you are having fun.

Remember you cant please all the people all the time.

Bill

Stonebrain · « **Reply #15 on:** July 07, 2009, 09:46:27 AM »

"Do you have a value in mind? I just figured these wind generators are typicly used to charge batteries and Im trying figure wich unit does that best."

very good question jerry,

Well,an important thing is "power=I>2*R"(power is current squared multiplied by the resistance)

Your (very usefull) battery tests gives powervalues in the range of 20 to 50 watts,

at 12v the current values must in the range of 1.5A - 4A.

If you apply these numbers to the above formula,I come to a range of 3 - 7 ohm.

Of course these are wild guesses.

Probably a range of 2 -20 ohm will be adequate.But I hope someone correct if my guesses are wrong.

If you have two resistors of 5 ohm you have allready 2.5 ohm(paralel) 5 ohm(of course)

and 10 ohm (series).But don't forget to take the resistance of the alternator in acount too.

Why doing it?

If you going to vary the load from low (=high resistance) to high(=low resistance)

you will find that first the blades are spinning fast but don't produce power,because at high resistance there isn't any current.

Then if the resistance goes down, the speed of the blades goes down and start making current.

If the load gets higher the speed of the blades goes down and produce more power till the point they going in stall.This is the point where the blades make maximum power for the given windspeed.

If you make load still higher finally the speed of prop goes down much further and produce less power.

If you compare the maximum power output with the results from battery loading you know how well the alternator is matched with the prop for battery loading(only at the given windspeed of course).

Of course,I'm just one of the 'you should do this or that'-guys.I didn't do anything like this myself.It's just my understanding of flux's lessons.I might be completely wrong.

cheers,

stonebrain

Jerry · « **Reply #16 on:** July 07, 2009, 05:11:32 PM »

Hi Stonebrain.

I think one of the problems with resistor loading is. The alt will be under some load from the get go.

This will ofcource will cause some stall at the begining. With battery loading the machine is able to free wheel or no load till it reaches cut in rpm.

After that the faster the blades spin the heavyer the load. I you load the genny down prier to cutin with resistors it may make it harder to reach cutin at the lower wind speeds.

Jerry

Stonebrain · « **Reply #17 on:** July 08, 2009, 01:46:41 AM »

Maybe let it start up without any load and only apply the load when it's turning allready.

stonebrain

ghurd · « **Reply #18 on:** July 08, 2009, 08:13:06 AM »

Hey Jerry,

If you get bored...

Have something that may help the garbogen.

Try hanging a fat cap on each of the bridges outputs.

Nothing fancy, no other changes. Just stick a cap on the +/- of both bridges.

If the bridge's outputs are wired close together, just one cap would be enough.

I expect it will help with the lower power times.

Might help more if the bridge to battery wire is long, like a full size tower to battery wire.

Might not help at all.

G-

Stonebrain · « **Reply #19 on:** July 08, 2009, 10:03:56 AM »

After that the faster the blades spin the heavyer the load. I you load the genny down prier to cutin with resistors it may make it harder to reach cutin at the lower wind speeds.

With resistors there is no such thing as cut in speed.

Not sure you understood what I tried to explain.

cheers,

Stonebrain

Jerry · « **Reply #20 on:** July 08, 2009, 08:52:05 PM »

Hi G.

Problem is in the Garbogen the DC outputs of the start and run winding diode bridges are wire in perelell.

So if you connect a cap to 1 you've also cennected it to the other.

The cap at this connection has the same effect as the battery and visa versa.

Thats why the cap thing don't apply to Garbogrens.

Jerry

ghurd · « **Reply #21 on:** July 08, 2009, 09:29:36 PM »

I know what you are saying,

but I got a 7% increase on one phase of a mini ECM.

The other 2 phases were not connected for the test, because I expected the gain would be more dramatic using 1 phase. I would have done more testing at the time but only had 1 decent sized cap.

I believe it would help a 2 phase, like the garbogen.

All it would take is a quick bench test of full size garbogen with a good sized cap on the DC side of the bridges.

And I believe You may be the only guy with a garbogen, big cap and a lathe.

I don't believe it would have much effect with 3 phases. A little.

Not sure if you saw what tests I managed around the holidays.

http://www.fieldlines.com/story/2008/12/15/22115/667

G-

Perry1 · « **Reply #22 on:** July 12, 2009, 12:20:55 AM »

Hello. I have read most of your wind tunnel tests and I think you have done a fine job. From what I understand you are normalizingyour windspeed for comparisons sake but have you considered generating a power curve for your different configurations? I think it would provide a lot of insight on you performance. Looks like your setup could do it easily.

Perry

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Author Topic: Todays wind tunnel test. (Read 2938 times)