Author Topic: Blades stalling  (Read 14372 times)

0 Members and 1 Guest are viewing this topic.

Offline niall

  • Sr. Member
  • ****
  • Posts: 299
  • Karma: +16/-0
  • No Personal Text Set by User
Re: Blades stalling
« Reply #45 on: January 03, 2017, 02:12:38 pm »
looks good ... :)

had you any trouble adapting it to the alt mounting shaft ?

the balance musnt be to bad if it starts up that easy....

when the wind drops does the prop tend to fall back to one position ?

maybe its that blade thats tracking a bit off , that will try to wobble the alt and at your height i " guess " it amplifies any mis balance/tracking ......i only helped working on one mast that went to 20m here and its not a quick job taking it down to reset balance......so cant advise much

 6676-0

its all knowns or unknowns from here out  :)

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #46 on: January 03, 2017, 03:46:10 pm »
It does start in lite wind but I'm pretty sure it's not balance properly.  At higher rpm the wobble goes away.  Tonight we have 15-20mph wind and I'm curious to let it fly in that for a bit, but scared at the same time.  Scared that I may not be able to stop if I turn off the brake switch.  I'm at work for the next 3 hours, the wind is blowing at the house but she is locked down. 
Just yesterday we had very lite wind and I can already see the potential of these blades.
There was no problem bolting to the alt, 3 blades with the triangle on the face, screwed together and all that bolted through to a steal 1/4" disc.  Went together nicely. 

Offline niall

  • Sr. Member
  • ****
  • Posts: 299
  • Karma: +16/-0
  • No Personal Text Set by User
Re: Blades stalling
« Reply #47 on: January 03, 2017, 04:27:23 pm »
fear is good ....not natural but good .....time to calm those blades .....

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #48 on: January 03, 2017, 08:06:20 pm »
Ok, fear is gone, all is well.  Took it off the brake, had my 500w  11-30v inverter and 2 1000w 22-60v inverters in parallel.  It makes great power compared to what I'm used to. The 11-30v inverter controls the turbine really well, but when the wind gusts from 12mph to 17 the small inverter can't load it fast enough and the voltage comes up and the big inverters turn on to help control it.  Works great! 
So I was curious, I unplugged the small inverter and let it spin, but it didn't make as much power, didn't record anything, but maybe 50w less in the same wind.  It does spin faster but makes less power, not sure why. 
Another thing, these blades make a lot of noise.  Well it sounds like 1 blade making noise but it sounds like an alien craft landing in my back yard lol.  I don't know how to describe it but I can here it in my house.  The sound gets louder the harder the wind blows but not related to the turbine rotor  speed. 

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #49 on: January 04, 2017, 08:41:57 am »
The noise appears to be associated with the amount of load. More load more noise. 

Offline hiker1

  • Full Member
  • ***
  • Posts: 178
  • Karma: +13/-1
  • hiker
Re: Blades stalling
« Reply #50 on: January 05, 2017, 12:43:41 pm »
Could be that warped blade..catching more air ..makin that noise..when under load the air dosent slide over as easily and builds up a bit..  To balance my blades I mount on a free spinning shaft...then give a spin...then just add weight to the hub on the light side....adding weight to the blade tips..isn't the best idea....tried that once...in a good wind the blade tip broke lose..
just do it

Offline niall

  • Sr. Member
  • ****
  • Posts: 299
  • Karma: +16/-0
  • No Personal Text Set by User
Re: Blades stalling
« Reply #51 on: January 05, 2017, 04:41:52 pm »
it could be the alt making the weird noise , i know some of Hughs machines have been grid tied and the hum/noise changed a bit/lot ..... ( louder ? )

with battery based systems ( i think ) things tend to be quieter......

i tried a very basic pwm controller ( no batteries/capacitors  ) on the mill ...kind of one big mosfet ......the modulation of the current made the alt sound like something out of war of the worlds ....a loud modulating groaning sound ....it basically turned the alt into a loudspeaker .......the mosfet blew up pretty quickly after and shorted the mill

wood blades are usually quieter than most as well....strange you hadnt the noise issue before.....maybe your new blades are pushing it harder ...

putting some big capacitors on the rectifier might help .....i,m not sure if thats a good thing for your invertors though ....it may help ...ish.......

i dont use batts on the mill now ...just big capacitors then into a pwm dump .......but the mill will kill them too over time

your watching it close though ......thats a good approach  ???

edit....just checking the caps on the mill rectifer  ....their 2 10000uF 80V electrolytics in parallel .....

your in unkown terrority .....

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #52 on: January 05, 2017, 07:25:27 pm »
Dropping the tower down tomorrow morning to investigate.
These blades make about 350-375watts in a 15mph wind, the blades that these replaced made 100ish watts in 15mph.  The original blades that came with the mill made 200watts @ 15mph.  It's pushing it harder. 
I believe there may be an imperfection on the top of the blade, may have to cut them down a bit, they are 2" longer then the drawing specs.  So I may remove these 2", go from 10'4" to 10'.  Then balance again.
 Headed to the store now to get a few materials. The tail is tiny for this big rotor and the boom is to small.  May get stiff to fix that too while it's down.  It will be back up tomorrow afternoon and we have 2 days of great wind.

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #53 on: January 05, 2017, 10:21:58 pm »
Got anxious, could this be the source of the whistle?

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #54 on: January 05, 2017, 10:40:43 pm »
Is this a decent way of balancing?

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #55 on: January 06, 2017, 09:07:10 am »
I cut an inch off each blade and filled the hole in the blade, no change.


Offline hiker1

  • Full Member
  • ***
  • Posts: 178
  • Karma: +13/-1
  • hiker
Re: Blades stalling
« Reply #56 on: January 06, 2017, 12:49:59 pm »
That's. Loud......dout if it's the knot....are the blade tips sanded smooth..tapered a bit ?...never had a carved blade do that..
just do it

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #57 on: January 06, 2017, 12:56:39 pm »
I the tips are cut clean off, straight

Offline rossw

  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 879
  • Karma: +35/-0
  • Grumpy-old-Unix-Admin
Re: Blades stalling
« Reply #58 on: January 06, 2017, 01:27:51 pm »
I the tips are cut clean off, straight

My original (commercial, chinese) turbine blades were like that, and it screamed like a banshee!


I took to them with an angle-grinder and feathered them


Then painted them with a hard epoxy paint


And finally sanded them smooth with fine wet and dry paper. After that, they were whisper quiet.
(I don't have a pic of them when finished, unfortunately).

Offline TurboMiles

  • Full Member
  • ***
  • Posts: 58
  • Karma: +3/-1
Re: Blades stalling
« Reply #59 on: January 06, 2017, 07:27:50 pm »
I tried rounding the tips and still makes just as much noise.