Re: Ammeter Question

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

Original poster: "Aaron Aab" <striker754-at-earthlink-dot-net> 

I think im just gonna use my clamp on meter. Cant see paying 70 dolalrs for
an amperage reading when i already have 6 clamp on meters around here

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, January 11, 2004 3:44 PM
Subject: Re: Ammeter Question


 > Original poster: dhmccauley-at-spacecatlighting-dot-com
 >
 > I would strongly recommend against using a digital handheld multimeter
 > unless its something that wouldn't mind losing.
 > Tesla coil circuits can have the tendency to put nice transients back on
 > your input power feed and i wouldn't want to risk
 > having a nice multimeter die because of one of them.
 >
 > I would rather use a true analog meter, or better yet, a clamp-on meter
for
 > measuring current.
 >
 > Dan
 >
 >
 >
 >
 >  >  > Where can I find an AC ammeter to go inline with my hot power
supply? I
 >  >  > would like to be able to measure the amps the transformers are
drawing.
 >  >  >
 >  >  >
 >  >  >
 >  > Digi-Key sells panel mount analog meters up to 50 amps a/c for $71.80
part
 >  > # is 180-1079-ND.
 >  >
 >  > If you are running under 1Kva, you can probably use your handheld
 >  > multimeter, just read the owners manual first, mine are only good up to
10
 >  > amps for short time periods.  If you are running high powers, you can
use
 >  > an amp clamp or a current transformer.
 >  >
 >  > I had this problem when I began useing more powerfull supplies.
 >  > Fortunately, I salvaged a 100:5 current transformer several years ago.
I
 >  > never new how to use it, but I found out on the list.  These are
expensive
 >  > when new but you can find them as surpluss.  The critical part in my
 >  > circuit is a .2 ohm 5 watt current sense resistor.  This allows me to
 >  > place my digital meter across the secondary, and if the circuit sees
100
 >  > amps, my meter only sees 5 amps.  I have to multiply the reading by 20,
 >  > but it works beautifully.  I use a gapped E-I core ballast, thie
current
 >  > monitor allows me to calibrate the ballast.
 >  >
 >  > Look for used panel meters or current transformers at Murphy's in El
 >  > Cajon, CA, C and H sales in Pasadena, or Gateway electronics, in San
 >  > Diego,  I think they all have websites.
 >  >
 >  > Good Luck and Safe Coiling,
 >  >
 >  > Thad Howard
 >  >
 >  >
 >  >
 >  >
 >  >
 >
 >