Twisted-pair wires to reduce surges [RE-wrenches]

[Rick Cullen - RV Power Products]

Here is what twisting does,

The electrical noise emitted or received from a circuit loop increases with
increasing "loop area". Suppose you have a pair of conductors carrying a
signal. If these wires lay right next to each other the "loop size" they
create is relatively small. If you then spread the wires several feet apart
from each other without changing the end point connections, the loop area is
now much larger. This larger loop will emit or receive more noise than the
smaller loop.

If you now twist the wires together, two things happen. One is obvious, the
wires are very close together. The other is that each of the loops in the
twisted pair could be thought of as its own little loop. Each loop is very
small which reduces noise. And key to it all, is that the noise
emitted/received from each of these little loops is opposite polarity
loop-to-loop-to-loop, i.e. + - + - + - + - + - + - and so on...  The noise
from one loop could be thought of as being canceled out by the loop next to
it.

Richard A. Cullen
RV Power Products, Inc.
760-597-1642 x102
Fax 760-597-1731
mail; rick at rvpowerproducts.com
www.rvpowerproducts.com




----- Original Message -----
From: "Windy Dankoff, Dankoff Solar" <windy at dankoffsolar.com>
To: <RE-wrenches at topica.com>
Sent: Friday, July 25, 2003 1:28 PM
Subject: Twisted-pair wires to reduce surges [RE-wrenches]


> Wrenches,
>
> I have always heard that twisted-pair wires pick up much less induced
> current from nearby fields. We all see twisted-pair telephone and
> other audio lines designed to reduce AC hum pickup. It seems to be
> well-accepted that twisting power wires makes a circuit safer from
> lightning-induced surges. R Perez reported in Home Power long ago
> that twisting the lines was more effective than shielding, per his
> experiments.
>
> I don't understand the principle.
>
> I twisted some wires together for a distance of 150 feet and it was
> not easy! I could have divided it into sections and twisted it in
> opposing directions in each section, which would have made it very
> easy, but since I don't understand the principle, I couldn't assure
> that it would be effective.
>
> Can anyone induce some understanding into my twisted mind?
>
> Windy
>
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