Current Transformer Use

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

Original poster: DRIEBEN-at-midsouth.rr-dot-com 

Hi all,

I posted this letter to the list a couple of days ago but
it apparently never got through, so I'm reposting. I apo-
logize if it ends up showing up twice: ...



I'm the one who started the "higher current ammeter sources"
thread but I fianlly decided that it would be easier to just
use a current transformer and measure a given proportion of
the high current with a smaller ammeter. I believe that Fair
Radio has some 0-150 amp ammeters that only have 5 amp move-
ment and require a current transformer to measure the up to
150 amps. Anyway, I got a 150:5 current transformer off of
ebay (thank God for ebay ;^)) for like $7 total (shipping in-
cluded) and I want to make sure that I'm doing this properly
as I have never actually used a current transformer before.
It's a toroid type and I just run the heavy current carrying
wire thru the toroid ring and measure the current from the two
small wire leads that come from the current transformer. I'm
pretty sure that this is the right way because I checked the
current with a clamp-on ammeter while measuring the current
reading from the small wire leads of the current transformer
and it showed exactly a 30:1 (150:5) current ratio (a reading
of 30 amps on the clamp-on ammeter showed exactly 1 amp from
the leads of the current transformer. So if I get a 0-150 amp
ammeter that only has 5 amps of movement I should be able to
accurately measure up to 150 amps with this ammeter in combo
with the 150:5 current transformer, right?

Thanks,
David Rieben