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KB2VXA > INFO 05.07.02 20:56l 57 Lines 2998 Bytes #999 (0) @ WW
BID : 50499_WT3V
Read: DB0FHN GUEST
Subj: Re: VK4LU
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Sent: 020629/1554Z @:WT3V.#JS.NJ.USA.NOAM #:50499 [Lakehurst] $:50499_WT3V
From: KB2VXA@WT3V.#JS.NJ.USA.NOAM
To : INFO@WW
Hello Ray and all,
Due to the delays encountered in message forwarding I keep seeing issues
I have addressed previously and tend to reiterate. Pardon me if I seem a
bit redundant.
I seem to remember a bit more clearly than you Ray (;->) so please allow
me to clarify a few things.
While the statistics based on medical reports don't include the actual
cause of death by electrocution, various other sources seem to indicate
the heart has little to do with it. By far the greater number which I
have observed show the general cause of death to be the tissues being
literally cooked by the passage of electrical current. I have seen some
gruesome sights of traffic accident victims literally cooked alive by
fallen wires, just to use one example. Have you ever seen the photos of
one who has been put to the electric chair? Believe me I can't describe
them here!
Just to clarify another point, you are talking of the Root Mean Square
(RMS) value of a waveform as being it's DC equivelent. That's a handy
point of reference, and yes, the peak value is 1.414 RMS. I guess that's
how we derive square roots, eh? (;->) BTW, square wire is often used in
transformers to concerve space. No, I'm NOT kidding this time.
The higher frequency you refer to is 400Hz which is the aircraft standard
because as you say in essense transformer and motors can use less and
lighter core materials making them more compact and lughtweight.
50/60Hz is pretty much the upper limit of power transmission frequency
not because of skin effect which doesn't appear until you get into the
hundreds of Kilohertz, but because of reactance losses in long lines.
There is an awful lot of inductance and capacitance in miles of wire so
what the transmission equipment sees is anything BUT a resistive load.
Take a look at the ratings plate of an induction motor and pay attention
to the box marked power factor. It will never be more than 90% because
it's an inductive load. The power companies compensate by installing
capacitors on the distribution feeders so the system becomes more
resistive and thier meters read correctly for one thing. That should send
some more interested people to the books learning about what VAR is as
opposed to Ohm's Law.
I have heard a bit about those much more efficient DC EHV lines but
frankly am ignorant of just how the system works. I would like to see
more on this because the topic suddenly fell apart just as it was
mentioned in bulls to 400Hz a few months ago. DC is the obvious choice
eliminating reactance losses in AC transmission lines. Just how do they
derive all that DC voltage from those Canadian alternators at Niagra and
what happens to it when it gets to downstate NY? Let's hear from someone
who knows!
*********************************
I'm a technician, not a magician!
*********************************
73 de Warren, KB2VXA
e-mail: kb2vxa@juno.com
Message timed: 15:55 on 29 Jun 02 UTC
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