Re: Ammeter Configurations

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


Tristin:

This is how we do it.  Since the coil is powered by an AC transformer, just
use a 0-250 full scale AC voltmeter that the dial faceplate is re-calibrated
in 0-16,363 Volts.  We usually round this off to 16,500 VAC full scale.

In normal operation the meter will read 14,400 Volts at 220 Volts input.
This is the Erms potential and the cap will fire at 1.414 * Erms (actually
this depends on your sparkgap setting for exact value).

A cheap easy way to accomplish the task and no messy HV dividers necessary.
Also, very accurate for TC work requirements.

We also do this with NSTs, just using a different value.  The math is a
simple ratio proportion:

X = (250 V. * 14.4 kV) / 220 VAC        X = 16.353 kV fullscale reading for
a pole xmfr

or X = (150 VAC * 12 kV) / 120 VAC    X = 15 kV fullscale for a 12 kV NST

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > I am in the process of trying to work out a way to measure AC voltage and
 > current flowing into my coil, and have run into a few problems in the
 > availability (and price) of AC meters.  I have worked out a method to use
 > the much cheaper DC versions that I can easily get.  Can someone please
 > offer some advice on if this setup will work, or if I have missed some
vital
 > point. (Wouldn't surprise me!).