Re: Watt meters

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Ed Phillips <evp-at-pacbell-dot-net> 

"Hi John,

It would be an interesting history lesson for the origin of the term
"imaginary" axis (maybe to compliment the term "real" axis).  Anyway, I
don't view the current as "imaginary" as in figment of one's
imagination.
It exist.  The current is real (don't mean the real component here) and
has
a phase relationship to the voltage.  It is just in mathematics that it
is
boken into its "real" and "imaginary" or as I prefer, its "real" and
"reactive" components where the "real" component is in phase with the
voltage and the "reactive" component is 90 degrees out of phase from the
voltage.

Take care,
Gerry R "

	The term "imaginary current" isn't commonly used.  It is convenient to
represent complex voltages, currents, and impedance in exponential form
(V=k*exp(j omega)) where j is the square root of minus one and is, I
believe, called an "imaginary number" by mathemeticians of which I am
not one.  The quantity [exp(j omega)] can be represented by
[(cos(omega)-jsin(omega)] which simply means the two factors have a
phase relationship of 90°.  In the late 1890's quadrature quantities
were often referred to as "quarter-phase", which is more explanatory.
More common usage is to refer to "quadrature" values. "Imaginary power"
refers to the reactive (non-lossy or non work-producing) component of
volt amperes.

Ed