14-3 shared neutral

[Ingvar Esk]

"Rich Grise" <richgrise@example.net> wrote in message
newsan.2005.02.26.21.24.29.841590@example.net...

On Sat, 26 Feb 2005 11:02:17 -0700, Kitchen Man wrote:

On Sat, 26 Feb 2005 13:02:19 +0000 in sci.electronics.basics, Fred Abse
excretatauris@cerebrumconfus.it> wrote msg
pan.2005.02.26.12.09.39.752208@cerebrumconfus.it>:

On Thu, 24 Feb 2005 21:48:13 -0800, John Larkin wrote:

Ah, I see now. Suppose two different computers calculate the number
"3". One adds 2+1, and the other takes the square root of 9. These 3's
are different, so there are actually two distinct kinds of "3".

That's only true for relatively large values of 3

But to get true phase shift, you have to take the limit as 3 approaches
zero.

I believe that Terry's original comment was meant to draw a distinction
between what's available on the two big black wires coming in to the
house, and the three 120 degree phases on the big transmission lines.
Some people are under the mistaken impression that two of those phases
are fed into the residence, rather than one phase split and inverted.
And yes, once you split and invert, you've got a 180 degree phase shift,
as well as a 50% attenuation, on *ahem* each leg. Or should I say bus?

But It Is Not A Phase Shift! It Is Merely A Polarity Inversion!

Some transvestites _look_ just like women - until you get under the
covers!

A phase shift oscillator works because the 180 degree phase shifted
negative feedback _looks_ to the opamp _exactly_ like in-phase positive
feedback. The opamp doesn't know it's in an oscillator - it's only
amplifying.

But just because it _looks_ the same, doesn't mean that it _is_ the
same.

Thanks,
Rich


Anothor way to illustrate the difference is to use a non-pure sine wave.

Let's assume you have some strange load that causes a spike on the top of
every positive period. In a scope you will see the spike move to left or
right with a phase shift and to move to the negative side in the case of
inversion.

/Ingvar