John,
I think the jury is still out on how damaging electrical fields can be
to
humans. The studies I have seen dealt more with overhead high tension wires
and proximity to electrical sub-stations. I repair medical equipment for a
living, and things like EKGs are very susceptible to nearby electrical
fields. Two of the worst offenders are computers and flourescent lights, so
we are exposed to this effect constantly. I have seen doctors offices where
it is impossible to take an EKG, because of the electrical interference.
Even so, my wife stopped using an electric blanket a few years ago after
reading about the possible dangers involved.
Keep in mind that what you are dealing with is an AC to DC transformer,
which will produce a good deal of heat. If you do shield this unit, make
sure you allow for adequate air movement to disipate this heat, or you may
be creating a more dangerous situation.
Mike Ellsworth
----------
> From: John McEwen <mmcewen@gpu.srv.ualberta.ca>
> To: Glenn Stauffer <stauffer@voicenet.com>
> Cc: mgs@autox.team.net
> Subject: Re: Electrical field effects
> Date: Saturday, March 29, 1997 7:40 PM
>
> Hi Glenn:
>
> Thank you for your prompt post. Unfortunately, re-location is impossible
> without a complete re-wiring of the trailer. All 115 volt and all 12
volt
> current passes through this unit. This is nearly an impossibility due to
> the manufacturing methods used and is comparable to relocating the
circuit
> breaker panel in a home. It would require a complete disassembly of the
> interior and the manufacture and installation of new cable runs as well
as
> the difficulty of finding a new location for the unit. It occupies
> approximately 1 cu.ft., which in a trailer is a difficult amount of space
> to find. It would also require the re-location of the power supply cord
> and exterior hatch/compartment which houses it. I believe the only
> practical solution is to shield it.
>
> John
>
>
>
>
>
>
> >The whole issue is open to great debate, but I'd sooner find a new home
for
> >the device. I read some papers that tell me that my clock radio is a
> >potential hazard, so I've moved it across the room. If you can relocate
> >the device, you'll know that you and your wife are safe - the fall-off
is
> >exponential, so merely locating it someplace where it won't be near you
for
> >extended periods of time should be enough.
> >
> >Glenn
> >
> >----------
> >> From: John McEwen <mmcewen@gpu.srv.ualberta.ca>
> >> To: mgs@autox.team.net
> >> Cc: alpines@autox.team.net
> >> Subject: Electrical field effects
> >> Date: Saturday, March 29, 1997 6:36 PM
> >>
> >> Hello list - especially those of you skilled in electrical
> >> engineering/technology:
> >>
> >> I have been presented with a problem by my wife. We are in the
process
> >of
> >> purchasing a new travel trailer which will allow us to take spring and
> >fall
> >> holidays. While the trailer will be too big to pull behind an LBC, it
> >will
> >> be possible for me to take a FBB (Fast British Bike) inside my van
when
> >we
> >> are towing.
> >>
> >> The problem is that the electrical converter in the trailer is located
> >> under the bed on my wife's side. She knows that it is not healthy to
> >sleep
> >> in close proximity to electrical fields. She wants me to "do the
right
> >> thing" and prevent any possible problem by eliminating the danger.
The
> >> converter converts 115 VAC to 12 volts (I am not sure whether this is
AC
> >or
> >> DC). It is a combination transformer and circuit breaker and draws up
to
> >> 55 amps. It is not cased but breadboard mounted and is surrounded by
a
> >> wooden box but open on top - under, and in close proximity to, the
> >plywood
> >> supporting the bed.
> >>
> >> My questions are as follows:
> >>
> >> 1. Do I have a problem or is the field involved negligible? Note
that
> >all
> >> of the electrical wiring in the trailer accesses this unit.
> >>
> >> 2. Would a metal barrier of some sort, attached to the underside of
the
> >> bed support plywood, act as a suitable protector?
> >>
> >> 3. Would this barrier have to be grounded to the chassis of the
trailer
> >in
> >> some way?
> >>
> >> 4. Is there a better suggestion?
> >>
> >> Thanks for your help. This is a serious concern for my wife and me.
> >>
> >> John McEwen
> >>
> >>
>
>
|