12-03-2004, 11:50 PM
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Re: Running electric blanket on DC?
On Fri, 03 Dec 2004 13:29:30 GMT, NoSpam@daqarta.com (Bob Masta)
wrote:
Quote:
On Thu, 02 Dec 2004 17:56:49 -0800, Eric R Snow <etpm@whidbey.com
wrote:
Greetings All,
I know this is silly but here it goes:
My wife and I keep our bedroom un-heated so it gets cold in the
winter. An electric blanket warms the bed before we get in. My wife
would like to keep it on all night instead of using all the extra
covers but is concerned that the "electrical magnetic field" emanating
from the blanket will give us cancer or something. I mentioned that
it's low frequency AC that people are all worried about and we are
subjected to it all day from wires in the walls etc so why worry about
the blanket? I know it's closer so any effect AC might have would be
greater from the blanket but sheesh! Then, I foolishly said that if
the blanket were run on DC we wouldn't need to worry. Now she wants me
to fix the blanket to run on DC. I took apart the control and it seems
like the heat control is just a bi-metal switch and the light is a
little neon bulb. Is there any reason why it couldn't be run on DC? I
envision a full wave rectifier and a capacitor. And it looks like
there is enough room in the control for these extra parts. Is there
anything inside the blanket itself that precludes Dc operation?
Thanks,
Eric R Snow,
Machinist, electonics hobbiest
I recall reading some years ago that in response to the
alleged problem, manufacturers were rearranging
the heating wire routing inside the blanket to
largely cancel the fields. I believe the new wiring
is just one big "hairpin" that is then routed around
the blanket. There is no loop to be inside of.
I might add that the original studies on the "problem"
were of ridiculously poor quality, both on statistical
and logical grounds. They probably would have
never gone anywhere except that a reporter wrote
up a big scare-mongering story in the New Yorker,
and suddenly eveybody figured this was a real
problem. Things like this can easily happen in
a scientifically illiterate society.
Just my 2 cents' worth!
Bob Masta
dqatechATdaqartaDOTcom
D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Yeah, I know the study was crap. But my wife prefers to believe the
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hype.
Cheers,
Eric R Snow
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