Re: AC/voltage basic physics questions, please.

On Jan 31, 2:39 am, HC <hboo...@xxxxxxx> wrote:
On Jan 29, 5:56 pm, "hhc...@xxxxxxxxx" <hhc...@xxxxxxxxx> wrote:





On Jan 29, 5:28 pm, HC <hboo...@xxxxxxx> wrote:

Thank you again for your post; it was the biggest boost to my
understanding I've gotten in a long time.

--HC

HC, you're more than welcome. The fact that you bothered to go outside
and actually look at the pole transformer says a great deal about your
interest in the subject.

I believe that you now have a rather good understanding of how
electrical power is distributed and supplied to our homes. Many people
don't.

Just a suggestion, but given your interest in the subject you may want
to purchase an inexpensive multimeter (for electrical use you can use
one costing less than $15 from Radio Shack or Sears). With this you
can verify the voltage from each side of the line to neutral, and the
voltage between the two 'hot lines'. One simple experiment is worth a
thousand words to solidify a concept.

Harry C.

Harry, I'm embarrassed to say I already have a multitude of meters,
mostly digital, but at least one analog.  :)  What has bothered me the
most is that I use this stuff so often (120v and 240v AC circuits),
and I've wired circuit breaker boxes, and run conduit and lighting,
and so on but never understood the  low-level part.  I just took it
for granted that it's AC, that connecting one hot to neutral gave a
120v supply and connecting the two hots gave 240v, no big deal.  It
was only when I started looking at three-phase generation that I
realized there was a very important concept about what I'd used so
long that I didn't understand; how can one wire swing voltage and yet
the neutral remains "safe" (okay, "safer" maybe).  It's like I knew
how to insert the key and start the car but didn't understand the
reciprocating internal combustion engine; yeah, I could use it and
change its oil, but I didn't know HOW it worked.  Which is okay if you
just want to drive the car and maybe change its oil but doesn't work
for beans when you need to know how to tweak the performance of the
engine.  Since the meters couldn't possibly tell me the low-level
stuff (just measuring potential but not indicating, for instance, that
one leg was at +240 and the neutral was at +120 so there was a +120
difference but simply only the +120 difference) I wanted to know and
since almost all my electrical knowledge is based in DC electronics
(and that's sparse) I was lost.

Thank you again; your post was the first I read that clicked with me
and my mind, and with other information posted, answered something
that had been eating at me.

--HC- Hide quoted text -

- Show quoted text -

Nuff said. Like you, I am a only practical 'electrician' only out of
personal necessity. I'm a physicist and E.E. by education, but only a
layman when it comes to electrical power disribution, and on that
aspect I was educated by electric company linemen. Same thing with
domestic gas plumbing, I was taught how to do if safely by guys in the
gas company. (They taught me that you check for gas leak on a
completed gas plumbing joint by the application of liquid soap applied
to the joint. Small bubbles are not a worry, since the sealant
contained with the gas will completely eliminate them a a few days).
It did! (For years I was a member of a Masonic Lodge that was
primarily membership consisted of employees of Rochester Gas and
Electric, where the Brothers were fountains of good and accurate
information.

That said, even as a physicist I'm pretty familiar with the NEC,
although I can only reference a copy at work. That pretty much clearly
show how electrical distribution systems, including services to the
home operate. It's definitely worth thumbing though in your local
libray, since I am not aware of any copies being availble on the Net.

As you may have noticed, here on the Internet there are many people
posting false information, either through ignorance or intention. When
it come to matters of safety, if is a very good idea to investigate
the credentials of these suspicious posters, most of who post under
ficticious names. I post using my real name, hence am rather easy to
track down, although I use an obsolete email address when posting, due
to spam attacks. I'll gladly post my real email address on request,
although most of the posters on rec.pyrotechnics already know it. Oh
yes, pyrotechnics is one of my rather eclectic hobbies..

Harry C.

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