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>
To: "RE-wrenches" <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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