Author Topic: Once again in 3-part (phase) harmony  (Read 11299 times)

0 Members and 1 Guest are viewing this topic.

JW

  • Development Manager
  • SuperHero Member
  • *****
  • Posts: 2402
  • Country: us
    • Flashsteam.com
Re: Once again in 3-part (phase) harmony
« Reply #60 on: December 08, 2017, 05:45:10 PM »
I set the display resolution to the same as facebook

SparWeb

  • SuperHero Member
  • ******
  • Posts: 3388
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Once again in 3-part (phase) harmony
« Reply #61 on: December 08, 2017, 05:45:31 PM »
Or Maybe it's the zinc fumes....
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

JW

  • Development Manager
  • SuperHero Member
  • *****
  • Posts: 2402
  • Country: us
    • Flashsteam.com
Re: Once again in 3-part (phase) harmony
« Reply #62 on: December 08, 2017, 05:52:40 PM »
:)

I did some tig welding on a Briggs and Stratton cyl head and it smelled like onions. On of the more experienced welders around me, said hey watch out for that the alloy is making poison gas.

Galvanized coated steel is easy to grind before welding and you get a better weld. 

SparWeb

  • SuperHero Member
  • ******
  • Posts: 3388
  • Country: ca
    • Wind Turbine Project Field Notes
Re: Once again in 3-part (phase) harmony
« Reply #63 on: December 08, 2017, 06:34:00 PM »
That mast support is nothing like the sheet-metal plate pictured above.  I'm not ready to believe that a heavy mast anchor fitting like that could just wobble around making noise unless the bolts are loose somewhere.  If you've checked the fasteners, and still hearing a noise, then something else is moving and this plate is just part of the path.  Rather than speculate more about the source of the noise, here's something to consider:



https://play.google.com/store/apps/details?id=com.nfx.specscope

If that's not fancy enough for you:



https://play.google.com/store/apps/details?id=com.keuwl.spectrumanalyzer

Not that I know if you have an Android phone or an iPhone, but if dozens of examples like this exists for my android phone then you should be able to find an equivalent in iPhone, if that's what you have.  It's pretty amazing when you find high quality software like this.  For free!
I installed these on my phone, and I've found them surprisingly useful and interesting to use.  I have watched it measure the engine RPM's change in my car, and on an airplane.  I have monitored the vibrations in my own tower with it, too.

Next time you climb up, run the app and point the microphone at various locations to "sniff out" the source of the noise.

No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

MattM

  • Sr. Member
  • ****
  • Posts: 435
Re: Once again in 3-part (phase) harmony
« Reply #64 on: December 09, 2017, 06:49:09 PM »
Quarter inch supporting 5 HP motors get enough flex to oscillate things nearby, there is absolutely nothing to suggest the plate would not be prone to the same.  Steel is many characteristics, elastic being one.  Regardless if the plate is a quarter or an inch or a foot in thickness, it has the same elasticity.  Flexibility isn't steel's only trait.  And nothing suggests and nobody specifically implied the vibration originated from the turbine.  The waves may be traveling in three dimensions up and down the mast.  Temperature changes and all sorts of environmental inputs can create the vibration.

kitestrings

  • Hero Member
  • *****
  • Posts: 781
Re: Once again in 3-part (phase) harmony
« Reply #65 on: December 11, 2017, 07:45:23 AM »
Quote
That mast support is nothing like the sheet-metal plate pictured above.

That's right Spar, the lower plate is much heavier, sorry for the confusion.  It is the mid-plate that is my adapted use of the 25G R-AS25G.  I believe there is a resonant frequency ~110-115 rpm where this light gauge plate vibrates/buzzes.  A don't believe there is anything loose, but I certainly will be checking.

Quote
And nothing suggests and nobody specifically implied the vibration originated from the turbine.

Matt, I think the turbine is the source here, as it only does this when we get a bit above cut-in ~300 watts or so, and about 70V in/ 110 rpm.  I believe it is this clipping ripple discussed earlier, but I think the augmentation thru this plate can be mitigated.

~ks

Mary B

  • Hero Member
  • *****
  • Posts: 809
Re: Once again in 3-part (phase) harmony
« Reply #66 on: December 11, 2017, 03:46:32 PM »
You could bolt an angle iron bracket across the bottom of the plate. If it is the source of the vibration it would change the frequency. But I suspect you are hearing the tower legs vibrate. My house brackets Rohn 25 antenna tower makes a heck of a racket in high winds as it vibrates.

MattM

  • Sr. Member
  • ****
  • Posts: 435
Re: Once again in 3-part (phase) harmony
« Reply #67 on: December 11, 2017, 06:32:17 PM »
I remember the location of guy wires playing a big role in vibration.

SparWeb's suggestions would help diagnose the source of you could record wind speed, too.  Each rotation of the turbine disrupts airflow each time the blade passes in front of the mast.  An out of balance turbine would have a similar frequency, but a different trough pattern. Sound forms might suggest something altogether out of sync with the turbine. Knowing the frequency would pinpoint more specifically the type of vibration.  It could be something as simple as a broken  allowing tangential rotation of an isolated segment of the tower.

kitestrings

  • Hero Member
  • *****
  • Posts: 781
Re: Once again in 3-part (phase) harmony
« Reply #68 on: January 15, 2018, 02:22:05 PM »
I haven't been able to follow up on this - most of the fixes are best in summer weather anyway...

A curious thing though... we had a freezing rain, sleet, snow event late last week.  Temp's were at record highs ~50 degF Friday, and then back to -10F last night.  The blades, tower, mount all had a thin frozen layer of ice, but I started the turbine on Saturday morning.  It had been lulling about, so there didn't seem to be any imbalance.  The output was a bit diminished I'd say, but the blade whistle was totally gone!  And, the plate vibration was also negligible.

On Sunday I scampered up to look it over.  The plate and tube were sort of welded together with a seal of ice.  The blades had a smooth, but irregular coating.  There was virtually none on the leading edge, heavier near the thickest cord section; spottier on the trailing edge.  (Should've had my camera).