Author Topic: Blades stalling  (Read 2641 times)

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Offline TurboMiles

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Blades stalling
« on: November 30, 2016, 09:06:56 AM »
Can someone recommend a blade set and hub that I can purchase for my 1000 watt max turbine.
My currently blades are a 5 blade set from mw&s called g5, they are stalling in 15+mph wind. Or would deleting 2 blades be a better option?

Offline niall

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Re: Blades stalling
« Reply #1 on: November 30, 2016, 02:47:53 PM »
Hi Turbomiles

i think i know those blades , its hard to get much out of them  , something like the ametek tape motors might match better . the swept area isnt very big.

a picture of the alternator and tail would help  (lots of variables)   but if it can put out 1k at a safe rpm consistantly without overheating   i,m guessing youd be looking at a standard 3m ( minimum ) diameter prop , 3 blades .....its will depend on the characteristics of your alt and your furling tail set up

if you dont mind nipping away at wood its not too hard to carve a set ...nothing fancy and will work just fine

mounting them onto your alternator could be tricky as wooden blades will be a lot heavier ( more stress/bearing load ) than the mws plastic ones .

taking off 2 i dont think will help ....it sounds like you need a bigger swept area to overcome the stall  .....ish   

i think if you change one aspect of the mill........................you almost denfinetly have to change a few more

there was one commercial mill ( a whisper maybe ) that used blade extenders at the hub to increase swept area a bit , the extenders were left out on its smaller cousin ( same blades ) .....an option but i,m not sure about that though ...... 

good luck with it  :)


   

Offline TurboMiles

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Re: Blades stalling
« Reply #2 on: November 30, 2016, 09:34:28 PM »
Thanks for your help!
It's an HYE 1000L, factory blades snapped off, MW&S G5 blades replaced them.  It's always had a tracking problem so I modified the tail and tail boom.  It tracks so good now but doesn't make power above 14/15 mph.

Offline TurboMiles

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Re: Blades stalling
« Reply #3 on: December 01, 2016, 10:31:27 AM »

Offline niall

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Re: Blades stalling
« Reply #4 on: December 01, 2016, 03:23:48 PM »
 :)

ok i see the pics now

those mws blades are different to the ones i had ......mine were the smaller " game of thrones  " variety , those look much better

so you have roughly a 2m diameter prop . sticking to the stall issue you mighnt have to go much bigger to improve the situation a bit . a 3 blade 2.2m maybe ...

i,m not sure i,d like to push more than 500w out of the alt , theres plenty of posts on the net of burned out coils on alts slightly on the edge . i,m not positive about that but you dont want to push for the high figures ...more consistant lower power levels would be easier on the alt and let it furl out early

the ebay blades ...a 2.6 m prop then , now seeing the alt i think their to big and if there good quality and run as fast as they should they might burn out the alt. plus......... there fibre glass and might ( probabely will ) be pretty heavy , possiblely 3 times heavier that a basic carved cedar wood prop of the same size , thats going to be hard on the linear bearings in the alt ...not good......and your going to have to customize the hub mount to suit the alt .....

your really in ideal terrority for carving a 2.2m 3 blade prop from something like cedar or any reasonably clear wood , if it doesent work out its really only cost you your time and its nice to see your own work up there.....

from the very little experiance i have and reading others posts about matching the prop to the load its a very tricky business getting it right first time  ( i never could ) especially of ebay .....i bought 3 sets online and none of them worked out ...almost.......but not ....its hard to tell with the ebay postings what quality you actually get.

i,m still wondering about some short 6mm plate extensions for the prop blades at the hub ...its not ideal but a cheap experiment , hacksaw and drill terrority .....if it doesent work thats ok   

when the prop goes in to stall what power is the alt roughly putting out Turbomiles ? .....your mast looks pretty high

sorry not really much help   ???

ps....if you are tempted to make a wood prop heres a link to a nice 2.3m design http://www.scoraigwind.com/selfblade/index.htm
its a powerfull prop so furling would need to be adjusted
 

Offline TurboMiles

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Re: Blades stalling
« Reply #5 on: December 01, 2016, 07:47:54 PM »
This is the history, factory hye1000l on a 55' tower.  Basic 80 amp eBay rectifier with 2 eBay1000w 22-60v grid tie inverter.  When the turbine would stay in the wind I could see 1200-1300 watts max.  Typical 200-400w in 13-18mph wind, it worked great.  Then a storm took the blades off.  These G5 blades are 37" long, it's almost 80" swept area and the stock blades had a swept area of 77", same hub.  These G5 blades are consistent in wind from 6-9mph.  6 is worth 5 watts, 7 10 watts, 8 20watts, 9 40 watts, but when the wind hits 10 it goes to 50 maybe, 11 maybe 50, a lot of times I see the power go down.  It requires about 18mph to achieve 100 watts.  I had a slip ring problem do I deleted it, connected directly now.  Had a rectifier problem, homemade a substantial rectifier.  The only thing left is the blades.  If I disconnect the turbine and let the wind spin it up and connect it again, I see huge numbers, then it just falls off over the next few seconds. So where the power falls off is at 10 mph and it's making about 50 watts.  I see my blades making power on YouTube, so I don't understand why they don't make power on my turbine. 
The turbine does not have a furling tail, it is fixed.

Offline TurboMiles

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Re: Blades stalling
« Reply #6 on: December 02, 2016, 12:57:30 PM »
I have found that removing 1 of the 3 phases from the rectifier makes more power then all three connected.  Does that mean anything?

Offline oztules

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Re: Blades stalling
« Reply #7 on: December 02, 2016, 01:54:55 PM »
Yes... it means that you have a poor matching of the load to your blades.... ie the tsr of the blades is too high for the stiffness of your alternator.

You can either

1. use a higher voltage battery bank, and that will change the behavior,

2. carve different blades.

3. leave two phases off so that it can run at a faster speed as you have found,

4. Put in three transformers to step down the voltage to the batteries. ( or a three phase transformer )

5. Use a buck converter to step the voltage down.

6. Place some resistance in the DC line to allow the blades to run up faster. You lose power in the resistor, but the blades will run faster and should compensate with more power over all.

7. Throw it away and buy more solar :)


..............oztules
Flinders Island...... Australia

Offline TurboMiles

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Re: Blades stalling
« Reply #8 on: December 02, 2016, 01:58:48 PM »
Thanks for all the options

Offline niall

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Re: Blades stalling
« Reply #9 on: December 07, 2016, 06:08:03 PM »
55 foot tower ...thats impressive ..a long way up,,,

Offline TurboMiles

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Re: Blades stalling
« Reply #10 on: December 09, 2016, 03:50:58 PM »
And its still not is the best wind,  too many trees

Offline TurboMiles

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Re: Blades stalling
« Reply #11 on: December 09, 2016, 03:54:39 PM »
And it has begun

Offline niall

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Re: Blades stalling
« Reply #12 on: December 09, 2016, 04:22:28 PM »
 :)

it seems it has ....welcome to the dark side turbomiles  ...whats the diameter ?

the blades look good and i,m sure will go like a scalded cat .....you may well need some kind of furling mechanism now , especially at 55 feet and when the weather goes to pot .....everything will go variable and the gremlins will try to come out and find the weak spot

good luck with the carving........

Offline TurboMiles

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Re: Blades stalling
« Reply #13 on: December 09, 2016, 05:03:40 PM »
Just under 10', each blade is 4' 11".  Planning on building a jig and rough cut with a chainsaw.
I don't plan on furling this one but the axial that I plan on building will furl.  Will try to control it with 2000 watts of load and 3000 watts of dump. Maybe it will kill my coils, we shall see.

Offline TurboMiles

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Re: Blades stalling
« Reply #14 on: December 09, 2016, 11:41:41 PM »
How am I doing?