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Re: [TCML] By-passing GFI on an NST



Dennis,
 
Try measuring the resistance between the white wire #4 and the orange and  
blue wires. The primary should have around 1 Ohm or less DC resistance. I  
suspect it's the blue wire, which would connect to the black wire, with white 
to  white like you have it. I suspect the orange wire is used to  trigger 
the GFCI. 
 
Tony Greer
Special Effects Neon
___________________

In a message dated 2/7/2010 3:03:21 P.M. Central Standard Time,  
otmaskin5@xxxxxxx writes:

Hi, I have been trying to bypass the GFI  circuit on a 9/60 NST without 
success.  The NST is potted with the standard  black tar substance, but 
fortunately the GFI unit was located in an open corner  space that was walled off & 
separated from the potting material.  With  a little work, I was able to 
wiggle the GFI unit free from the space & clip  the wires leading to & from 
it.  That left me with 6 unconncected wires  inside the NST case.  I connected 
those wires in a way that I thought would  properly complete the NST 
circuit excluding the GFI.  When I tried testing  the NST gradually turning up my 
variac, it kept tripping the GFI on the garage  outlet.  The NST never got 
to the point of humming like they usually  do.  I've been able to run coils & 
jacobs ladders off that outlet  without problems.  So I'm thinking I've got 
the NST wired wrong.  Can  anyone out there offer advice on getting the 
connections right?

The  transformer is a 9/60 Franceformer cat #9060 P5C-2.  I designated the 
wires  #1 through 6 to help clarify which wires were which, the numbers are 
not  designated by the factory.

There are 2 wires coming out of the tar on the  side of the NST where the 
external 120v input terminals are located:
#1 Black
#2 White

There are 3 wires coming out of the tar on  the opposite side of the NST:
#3 Orange
#4 White
#5 Blue

There is 1 wire connected to the metal case:
#6  Green

Here is how I connected the wires:
#1 Black to #3 Orange - I  tied these two together because the went into a 
spot very close to each other on  the GFI unit.
#2 White to #4 White - these 2 also went to a spot on the GFI  unit right 
next to each other.
#5 Blue to #6 Green - thes wires also went to  a spot on the GFI right next 
to each other.

Seems like it should be  pretty straight forward.  However, since my first 
attempt didn't seem to  work, I thought it would be better to get some 
advice before reconnecting wires  blindly & maybe risking possibly damaging 
something.  I found some info  on NST/GFI in the pupman archives, but it didn't 
seem to address my specific  situation.  I also looked for a schematic on the 
manufacturer's website,  but they didn't have one.  I'd be much obliged for 
any help you can  provide.  Thanks, Dennis Hopkinton MA
 
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