Ron Young wrote:
Mike,
Some interesting points, thank you. I would have attributed the
problem to several of the mentioned issues, medications (HRT),
clenching, tension... But what happened a couple of days ago makes me
wonder. I turned on the inverter without her knowledge and within two
minutes she was complaining and asked me if it was on. It was right at
quitting time and she was out of the environment within 7-8 minutes
but the next day she complained that she had a "migraine" that night.
Ron
Yep, it's gotta be the sound. I'm 95+% sure...
If you want to try to tweak things, a decent microphone running into
a higher sample
rate A/D on a laptop with (96 kHz or 192 kHz) and a program with
spectrum analyzer can help
to adjust things to possibly quiet it down some. Maybe if you know
someone into audio you could
have them come over and bring their goodies to help you sorta "see" the
sound in the room.
Then, you could try tweaking things lik, tightening screws and putting
in a baffle or
something until that 20 kHz frequency spike comes down, say, 10 or 20+
dB or so.
Might just work. But, then again.....
boB
On 4-Feb-10, at 6:41 PM, Ron Young wrote:
forwarded from earth2
Begin forwarded message:
*From: *"Michael Gullo" <mgul...@comcast.net
<mailto:mgul...@comcast.net>>
*Date: *February 4, 2010 5:47:56 PM PST (CA)
*To: *"RE-wrenches" <re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
*Subject: **Re: [RE-wrenches] Inverter causing migraine?
**Reply-To: *RE-wrenches <re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
Hi Ron and the group,
The attribution of negative health effects to exposure to
electromagnetic fields or activated electric equipment has not been
confirmed in random double-blind provocation studies involving
persons reporting hypersensitivity to electricity. Before we accuse
are hard-working inverters, let's look at some facts. There are 13
different categories of headaches which are divided into over 129
sub-types. Many people call every headache they experience as
migraine when in fact there are specific inclusion criteria to make
diagnosis of migraine. The "rubber band tightening around my head"
is a classic symptom of tension-type headache. Given a mid 50's
female, there are more likely one or more provoking factors:
medications, sleep pattern, hormonal replacement therapy, stress
(clenching, TMJ), smoker, foods (aged cheese, alcohol, caffeine,
chocolate, dairy products, MSGs, etc). Does she work at a computer
using a chair with no arms and no lower back support with a monitor
slightly higher than eye level? This is an extremely common scenario
in which the employee comes to work symptom-free and by 12 or 1:00
develops a headache or neck ache. If she really wants some answers,
she will need to keep a headache diary for several weeks and seek
professional help. You could cycle the inverter on/off to see if
there is a direct correlation between the incidence of the headaches
and runtime of the inverter. BTW, the placebo effect, as mentioned
in other emails, is between 40-60% effective at resolving symptoms.
Hope this helps a bit.
Mike
Michael Gullo
Solar Solutions LLC
Marlton, NJ
NABCEP Certified PV Installer T
Diplomate American Board of Orofacial Pain
----- Original Message ----- From: "Ron Young"
<solarea...@solareagle.com <mailto:solarea...@solareagle.com>>
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
Sent: Thursday, February 04, 2010 1:19 PM
Subject: Re: [RE-wrenches] Inverter causing migraine?
Bob,
Not a customer, an employee who works for me. She is mid 50's and
has very good hearing. You may be right about sound. I also think
there's a significant portion of psychosomatic in the mix but I
wanted to find out if there were other instances of people
experiencing distress from inverter operation just to rule out the
possibility -or take it into account.
I know that some people are becoming more sensitive to
environmental influences but this inverter is quiet, just the usual
fan sound occasionally. I used to be able to hear the sound of an
ultrasonic alarm system back when I was in my 20's & 30's - now I
just hear ringing in my ears.
Ron
On 4-Feb-10, at 1:30 AM, boB Gudgel wrote:
Dan Fink said:
"That's a tricky situation. There are only two possibilities
for what's causing the problem; sound or electromagnetic radiation"
I'm betting that it's sound. Remember how you could
hear televisions singing
away at 15 kHz ?? That still gives some people headaches.
How old is this customer ?? I'm guessing he's young because
it's most likely because he
can hear the inverter switching. We just can't normally
hear them.... The FX/VFX
inverters switch at around 20 kHz which some people can still
hear. Especially younger ones
with better hearing.
It's probably the transformer windings and iron acting as a
speaker/ transducer.
High frequencies are very directional so will usually respond
well to a thin wall of
padding between inverter and the rest of the inside of the house
or cabin.
That should help reduce the acoustical output.
boB
Dan Fink wrote:
Joel --
Good points. In a recent newspaper article in Boulder, CO about a
really bad PV install, the direct grid tie inverter was
mounted right on the outside of the wall from the homeowner's
bed. They finally had to have it moved--mostly because of
buzzing, but EMF was a concern too. It was basically less than a
foot from the guy's pillow.
Also, I forgot to mention that there are fairly inexpensive
EMF meters available from the same places that sell DIY
shielding materials.
The biggest source of EMF at *my* house is actually the E-Meter
measuring amp-hours. It even interferes with my handheld ham
and fire department radio FM communications on 2 meter.
DAN FINK
Renewable Energy Consultant
Joel Davidson wrote:
Ron,
Electromagnetic fields are produced any time you have
current flowing through wire. They are low frequency waves that
drop off rapidly proportional to the distance from the source.
Inverters, transformers, fluorescent light ballasts, motors,
clock radios, power blocks, microwave ovens, kilowatt hour
meters, service panels all emit EMF. There is no
practical way to block EMF. It passes through almost everything
including walls and even lead. There is no U.S. safety
standard for EMF. Some say 8 milligauss or more is dangerous
and 2.5 milligauss or less is safe.
I went through our home about 10 years ago using a
borrowed milligauss meter (thanks David Katz). Our utility
meter service had significant EMF, but that was not a problem
since it is mounted on an outside wall and there is a closet
between the living space and the meter. The EMF had fallen to
below 2 milligauss between the wall and the closet door. The
bedroom clock radio was the second largest EMF source in our
home. Moving the clock 1 foot away from the bed to the other
side of the night stand brought the EMF levels under 2
milligauss. Our SW4048 inverter emitted a field that fell to a
safe level 2 feet from the inverter.
I tell people not to put their bed against the wall where their
utility service panel or inverter is mounted. I also tell
them that the Japanese did a 2 year study of school children
riding the Tokyo subway (big EMF emitter) and found that there
was no danger.
Some sounds that most of us take for granted can cause physical
discomfort and even pain. SW4048 and other transformer and
electrical and electronic buzzing can be annoying. Also certain
wavelengths and intensities of light can cause pain and injury.
Joel Davidson
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