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RE: [TCML] NST failure ?? variac problem too
Yup,
Those variacs in my experience are junk. I had to loosen the screws so the
wiper would touch all they way around instead of half way. Buy an American
one off Ebay. You may have to buy a neon too. Unpot a France as the older
ones all seem to have cracked asphalt and are cheap. You could easily get to
90ma by halving the shunts on both sides of a 60.
I have several American made variacs now and they all work perfect. The low
ohms to ground on the primary of the neon doesn't seem good to me;-( My
shiny red China variac sits out in the rain as a tarp weight.
Jim Mora
-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Shaun Epp
Sent: Wednesday, December 03, 2008 3:43 PM
To: tesla@xxxxxxxxxx
Subject: [TCML] NST failure ?? variac problem too
Hello group,
Well I haven't posted here it a while, but I was testing a new NST filter
that I just built with my 12Kv/60mA NST and el cheapo variac and I popped
the breaker. The power switch on the variac was turned off, it's just a
switched hot and the dial was set to zero. I went to plug in the NST, just
as I inserted the plug into the variac the lights in the room dimmed and pop
goes the breaker : - 0
It turned out that the Hot and Neutral was reverse at the AC receptical
where I plugged in and the way that my variac is wire, a full 120 VAC to GND
went to the NST. Now I don't think that this should case the breaker to
pop. I'm under the assumption that the primary is floating and the
secondary is supposed to be center tap grounded. Please correct me if I'm
wrong.
I checked the NST with a ohmmeter I I measure 3.3 and 3.7 ohms to ground
from the 120VAC terminals. ???????
Each secondary terminal was about 2.5K ohms to ground. It's an Allanson
type 455B if that helps. Is my NST blown??
The variac is one of the china built white ones, a 2090VR. This incident
could have been dangerous! I think I have to put a different switch on it
that opens the hot and neutral. Anyone modified one of these?
thanks,
Shaun Epp
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