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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.
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Be a hero & convert it
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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.
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Just a FWB (no cap) & its DC - _definitely_ not AC anymore!
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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
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Valid data snipped...
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Yeah, I know the study was crap. But my wife prefers to believe the
hype.
Cheers,
Eric R Snow
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She wants you to convert it to run on DC? Put your full wave bridge in
the circuit. Presto - its DC - Yes its unfiltered DC but it _is not_ AC
anymore! I don't know of any studies that have shown low levels of
pulsating DC causing any problems
Thermostat shouldn't be stressed because of the pulsating nature of the
current - heat output should be the same - the neon light may be
somewhat dimmer (only if FWB is between AC cord & controller) because
just one side is flashing - that will prove its running on DC.
Depending on how much room there is in the control box & the wiring
arrangement, the preferred place for the bridge would be where the
actual heater connects to the controller - the thermostat & neon would
still be conducting AC but the heating element is running on DC. If that
is difficult (maybe because of the small wires?) -
Second best (but still very acceptable) would be at the AC input (cord)
side.
Please think "Safety" when working with AC mains.
Everyone comes out a winner
Kim