The only thing I'd disagree with is that current flows, yes, but electrons
stay where they are. They excite the next molecule when polarized in one
direction by current, but electrons don't move down a line even in DC.
Otherwise all the electrons would ultimately go away and you'd no longer
have molecules of whatever the carrier is and no current would flow. In
other words, an electrical current would be a catalyst that would change the
atomic weight of a molecule in DC. In AC the electron simply excites the
next molecule's electron in a positive direction, and then a negative
direction, doing this 120 times a second in a two phase system, 180 times in
a three phase system.
I recall Stephen Paul (RIP) having what turned out to be a rather heated
discussion here about the fact that electrons don't actually flow, but a lot
of people either didn't get the discussion, or have this weird idea that
electrons jump from molecule to another in the direction of current. Even
if this were true, the best case is that an electron would be shared between
two molecules in AC generation. But, in fact, the initially excited
electron only jumps to an excited state within it's molecule (more enegetic
orbit), which excites the next molecule, and then it drops back to it's
"steady" state when power isn't flowing. The only difference is the
direction of the phase, meaning current flow.
The kicker is in the fact that, at absolute zero you get a halt in brownian
movement, and yet you also get absolutely no resistance to current flow,
which absolutely means that electrons aren't flowing down a copper wire.
For reference of Stephens somewhat rambling post, read
http://www.google.com/groups?q=elect...dio.com&rnum=2
--
Roger W. Norman
SirMusic Studio
"Brandon Anderson" wrote in message
...
Umm... Well, if you equate current to electrons, neither of you is
"right."
If you measure peak voltage, than he's right in one regard, the voltage
does
fluctuate. The electrons don't get a chance to go anywhere, really, as
the
polarity of the electric field keeps reversing. Think of it this way:
even
the ground has electrons. The electric field of the neutral
(theoretically)
is the same as the ground, leading to no electric potential between the
two
(ground does have a charge, but everything is relative to it). Hot,
however, has a potential relative to ground of 120v RMS (US). This is, in
one cycle the field goes 0 to (-)120 (can't remember the actual peak
voltage) to 0 to (+)120 to 0. When the cycle is negative, electrons move
a
short distance from the hot wire to the neutral. When it is positive, it
attracts electrons from the neutral to the hot. Now, on a good day it is
safe to handle a live neutral, but I've read 80v from a neutral before,
and
almost always get zapped.
Oh, the above holds true to single phase only. Dual phase is a little
more
complicated because it involves the interaction of two fields relative to
each other... And I don't trust electricians; been in too many situations
where I've been shocked by shabby work and end up fixing it myself. You'd
find a physics book more informative than your electrician for sure.
--
____________________________________
Brandon Anderson
Lighting, Sound, and Video
http://www.bdanderson.com/
"apa" wrote in message
om...
I was talking to an electrician doing some work in my building and
started asking some questions about AC. My electrical knowledge is
quite limited, but in the course of the conversation, I said something
about the the flow of current reversing direction twice every 60th of
a second. He said "No, the ACTUAL current always flows in one
direction from the hot to the neutral and it's the AMOUNT of current
flowing that alternates." Isn't that the definition of modulated DC,
not AC? I couldn't make any sense of his explanation of what he meant
by "actual current", but he insisted that current flows in ONE
DIRECTION ONLY. I really don't get what he's talking about - but he's
the professional. Can someone fill me in?