gmcjetpilot
Joined: 04 Nov 2006
Posts: 170
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 Posted: Tue Apr 15, 2008 5:37 am Post subject: Shunts (Nerds!) |
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Bob, you're great, but lighten up. I am a Nerd. I have a
masters in engineering, and last time I mentioned that to
you, you attacked me and bashed engineering and
engineers from here to Sunday. I have lots of respect for
you, but that killed some of it, but I'm a nice forgiving
fellow. I have moved on.
As far as Nerds, I spend 5-6 years in undergrad and grad
school with an HP 41C hanging off my belt. I now dress
nicer and work out more, but I am still a Nerd at heart,
proudly.
As far as an AMP meter being a sensitive VOLT meter, it's
true. An AMP meter with out a shunt is a volt meter.
Basically we all are talking about D'Arsonval movement,
the way analog meters work, where current causes a EMF
(electromagnetic field) in a coil in an opposing direction to
permanent magnets, causing the needle to move. A
torsional (mechanical) spring or coil is calibrated to resist
the needle movement, thus reading a voltage (or current).
You don't need to be an engineer to understand how a
D'Arsonval movement works. I learned this when I was 12
years old, playing with my Radio Shack Science Fair
"160 in 1" electronic kit. However, now I can derive
Faraday equations (or Lenz) & explain the theoretical
physics with advanced math. That makes me a super
Nerd, proudly.
When I said magic Bob, I was being humorous, jocular,
whimsical, an attempt at being witty? Some people don't
need (or want) to know the details to wire a plane. I was
being causal, which is sometimes more productive when
addressing students, who might have anxieties about the
topic. It's just my style Bob, which obviously clashes with
yours.
I never taught "electronics" but I teach a lot of pilots, from
Student to Airline pilots, how the electrical system of a
Cessna to Boeing 747 works. Electrical systems are fun to
me and something I enjoy, not a place for argument or
politicking. It's just not a controversial subject to me. I just
want to help. I don't need to be perfect. As I have said Bob,
you have forgotten about the topic than I'll ever know, but
there is the off chance I know something you don't? I might
explain something in a way which gets through. That's all.
Cheers George the NERD!
PS thanks for the link. As a kid I broke many needle movement
taking them apart to see how they worked.
>From: "Robert L. Nuckolls, III" <nuckolls.bob(at)cox.net>
| Quote: | Subject: Re: Re: Shunts
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| Quote: | At 07:07 AM 4/14/2008 -0700, you wrote:
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| Quote: | >Oh my my. This is why people make fun of tech geeks and nerds, ha-ha.
|
>Interesting . . . it seems that the same folks would also
>make fun of neurosurgeons, master chefs and physicists.
>Individuals who poke fun at the assemblage of simple-ideas
>into useful inventions are themselves at-risk for not
>enjoying the benefits that arise from understanding . . .
>a kind of self imposed exile to ignorance that leaves
>them dependent upon those who DO understand.
| Quote: | > Yes voltage, current and EMF are all magically intertwined.
|
>Nothing magic about it. But the conditions under
>which they interact are not consistent. For example,
>just because there is voltage to be measured doesn't
>automatically translate to a current flow. Similarly,
>there are conditions where huge magnitudes of current
>flow with zero impressed voltage.
| Quote: | >Even the magic of the hall effect sender puts out proportional
>volts to current.
|
>Sort of . . . volts is proportional to the intensity
>of a magnetic field. The magnetic field can come from
>a variety of sources not the least of which is the
>field surrounding a current carrying conductor.
| Quote: | >But you all are right, there are coils in those mechanical gauges.
>However a digital meter will read directly off a shunt? Huha? What?
>Doha! ha-ha.
|
>Yes, the digital voltmeter takes advantage of the
>voltage drop impressed across a shunt as a result
>of current flow. The measurements obtained by this
>method are independent of simple-ideas involving
>magnetics.
| Quote: | >Bob your "VAM10_Interior_View link" is not working?
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>Yes, I corrected it in the posting that followed
>a few minutes after the first. The working link
>is . . .
http://www.aeroelectric.com/Pictures/Instruments/VAM40_Interior_View.jpg
>Bob . . .
between 0000-00-00 and 9999-99-99 [quote][b]
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