[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

how to bypass GFI



Original poster: "Dwight Harm" <dwighth-at-traxsoft-dot-com> 

I got 2 Franceformer 9KV/30ma transformers (#9030-PG-1) that I was told were
broken.  Taking off the top of the first, I found a GFI unit, looking
virtually identical to this old posted photo:
http://hot-streamer-dot-com/temp/Old2002Files/2002-05/NSTGFI-lidoff.JPG

However, the second was more interesting, as it was potted in CLEAR resin!
http://www.traxsoft-dot-com/images/NST-GFI-Jefferson9KV-30.jpg

Note that this circuitry seems more complicated than would be required for
simple GFI protection. 10 wires go into the package.  From ohmmeter
readings, I think the connections are as follows:

White - connects to external AC input labeled '-'
Black - connects to external AC input labeled '+'
Green - connects to external "GND" bolt, and to case
Yellow - connects to external "Return" bolt
2 (thinner) black wires - to reset switch, momentary, normally-closed.

Orange - one side of primary
Orange/blk - other side of primary -- 7 ohms between them.

Blue - LV end of secondary A -- 7K ohms to one HV external bolt
Blue/white - LV end of secondary B -- 7K ohms to other HV external bolt

There were discussions of these around 5/20/03, 7/21/03 and even back in
5/5/2002.  Some said it was easy to bypass GFI stuff, but none ever actually
said HOW (that I could find).  What I tried doesn't seem to work...

- Cut all the wires and removed the GFI unit.
- Connected blue, blue/white, and green (i.e., joined secondaries at 'center
tap' and grounded them), and connected to mains ground.
- Applied 120VAC across orange & orange/blk

Then I tried to draw a spark between each HV out and ground.  Only got about
1/16", and couldn't "stretch" it at all. (Too little current??)  Even
stranger, from one HV out to the other, I got NO spark at all!  Both NSTs
acted this way.  I also tried it with the secondaries not connected to each
other, no difference.

So, are the NSTs both broken in some fashion? Or is there something else
happening that I don't understand? Ideas?

Dwight