Re: HV Measurement - Back to Basics

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

Original poster: "Crow Leader by way of Terry Fritz <teslalist-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

180 volts error out of 15kV is 1.2%, which is less error than you should
expect from a typical panel meter anyways, not even taking into account your
resistors. If the 180 volt error is unbearable, take a screwdriver and
offzet the zero on the meter to where you think 180 volts may be. Problem
solved.

KEN

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, January 05, 2003 1:22 PM
Subject: Re: HV Measurement - Back to Basics


 > Original poster: "David Speck by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<dave-at-davidspeckmd-dot-org>
 >
 > Jim,
 > If you were not going to use a precision rectifier on the low voltage end
 > of the chain, then you would have to use a high voltage rectifier before
 > the dropping resistors.  I guess it's about a wash in terms of difficulty
 > -- building a 15 kV full wave bridge for the high end vs. a precision
 > rectifier at the low end of the divider network.  I guess that if you had
a
 > set of HV diodes available, then it wouldn't be too hard to tackle the HV
 > end approach.
 > Dave
 >
 > Tesla list wrote:
 >
 > >Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>"
 > ><jimlux-at-earthlink-dot-net>
 > >
 > > > tool, and make it the resistor closest to the meter, and hence,
ground.
 > >Of
 > > > course, I am assuming that you are measuring a DC voltage.  If you are
 > > > measuring unrectified AC MOT output, you will have to add a precision
 > > > rectifier circuit, a much more complicated issue.
 > > >
 > >
 > >Don't need a precision rectifier... The few tenths drop in the diode
bridge
 > >is insignificant compared to the huge drop in the resistor.  You
calibrate
 > >it empirically anyway, so the RMS/Average/Peak issue doesn't arise (that
is,
 > >you put in 15 kV ACRMS, adjust a trim pot til the meter reads FS, and
you're
 > >done).  If you were trying to measure a few volts, or make average
voltage
 > >measurements with varying waveforms, then a precision rectifier might be
 > >needed.
 > >
 >