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Matt,<br>
<br>
What you are hearing is alternator noise. It's caused by the
vibration from the permanent magnets passing by the alternator
coils.<br>
All turbines produce some alternator sound, some more than others
and the tower itself can act as a resonator, amplifying the sound.<br>
<br>
The reason you don't hear it when the turbine is unloaded is because
no current is being induced in the alternator coils, so there's<br>
no resistance pushing against the rotor magnets.<br>
<br>
Unfortunately, there's nothing much to be done about it.<br>
<pre class="moz-signature" cols="72">Roy Butler
Four Winds Renewable Energy, LLC
8902 Route 46, Arkport, NY 14807
607-324-9747 <a class="moz-txt-link-abbreviated" href="http://www.four-winds-energy.com">www.four-winds-energy.com</a>
Although no trees were killed in the sending of this message,
a large number of electrons were terribly inconvenienced.
</pre>
<div class="moz-cite-prefix">On 9/30/2019 9:44 AM, Matt Sherald
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CANWECJiotyAV_6JU1yzmCV0sOpAVVUNzOdPtEbh87gtriFbkVQ@mail.gmail.com">
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<div>Friends,</div>
<div><br>
</div>
<div>I've exhausted the Bergey tech support expertise on this
issue and I'm hoping someone on the list may have a solution
to share.</div>
<div>I have a customer with an older XL.1 on a tilt-up tower.
The machine has been in place since 2007. I've done some work
to it over the years including blades, yaw bearings, painting,
slip rings, brushes, rectifier.</div>
<div>The machine/property has a new owner who finds the noise of
the machine to be objectionable. The original owner also
noted the noise, but was not as dogged about resolving it.</div>
<div>The noise is best described as a "hummbuzzz" and it happens
when the machine rpms have slackened and then begin to
accelerate again. The transition causes some kind of
electrical harmonic that is not noticeable once the rpms
increase. So, if the machine furls out of a high wind and the
rpms drop then the noise begins as soon as it un-furls and the
blades begin to accelerate. The noise disappears as it comes
up to speed.<br>
</div>
<div>This noise does not happen if the machine is allowed to run
unloaded (with the breaker in the off position).</div>
<div><br>
</div>
<div>Anyway, I'd sure appreciate any thoughts. Many thanks in
advance!<br>
</div>
<div><br>
</div>
<div>
<div><br>
-- <br>
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data-smartmail="gmail_signature">
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<div>
<div>
<div>Matt Sherald<br>
</div>
PIMBY Energy, LLC<br>
</div>
<div>NABCEP Certified Solar PV Installer®<br>
</div>
<div>304-704-5943<br>
<br>
</div>
<span><a href="http://www.getpimby.blogspot.com"
target="_blank" moz-do-not-send="true">www.getpimby.blogspot.com</a><br>
</span><a href="http://www.getpimby.com"
target="_blank" moz-do-not-send="true">www.getpimby.com</a><br>
</div>
<br>
</div>
</div>
</div>
</div>
</div>
<br>
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