Re: Electrostatic Meters

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

Belatedly, ignore at leisure.

Found it:
	Electrical Measuring Instruments
	Drysdale & Jolley
	1925
	400 pp text on the design & Characteristics.
	(Not a vacuum tube in the bunch.  Nor a rectifer,
	nor a transistor....)
	While much of modern metrology is thus excluded,
	many of the principals involved still apply.

40 pp on electrostatic meters:
Paraphrasing:
	Advantages
	take 'no' current (1)
	no magnetic hysteresis
	no wave form errors (2)
	frequency errors (2)
	Loss of energy is negligibly small
	read correctly on DC and AC circuits. (3)

Now some of these are subject to qualification, and all
were made with respect to 1920s, and to power freq
applications, specifically:
	(1) is only true on DC circuits.
	(2) are true on power freq circuits.

As to the 'where does the 'squaring' take place, consider,
from the fundamental equation that the torque is a function
of, effectively, energy stored in the capacity of the vane
system and THAT (from the fundamental equations) varies
as V**2.

It appears that some, at least, for whatever reason have
been set up so that (3) does not apply.
--------------------
In General thought is apropos in using any measuring
instrument.  A common example is that many (most?)
meters labeled as 'RMS' are ACTUALLY _average_
reading instruments which ASSUME a neat sine wave and
indicate the RMS of THAT.  Neat Sine Waves almost never
exist in Tesla Coil systems.

Many 'here' know that, for some, a meter can easily
mean something else than what it seems to 'say'.

This specifically includes modern digital meters
in all price ranges.  The best are marvelous instruments.
Any, and some more than others, can be mislead...

	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me