RE: Some newbie questions

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

Original poster: "John H. Couture" <couturejh-at-mgte-dot-com> 


Aaron -

Sorry, I do not have pictures of the NST protection. It is just two separate
pieces of wire each with a loop. One wire is connected to the hot terminal
and the other is connected to ground. For a 15KV NST you need this short
circuit protection gap for each 7.5KV terminal. This cheap and easy and
effective gap for NSTs has been used by coilers for years.

John Couture

-------------------------------------

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, January 08, 2004 3:22 AM
To: tesla-at-pupman-dot-com
Subject: Re: Some newbie questions


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

Would I need to use the baffles if i have the top wire outside the tube and
the ground wire inside the tube? Not that its a big deal to put the baffles
in, jsut wondering.

So Im connecting the caps for protection from the case of the transformer to
the hot terminals, and the resistors from the hot terminals to the spark
gap?

Do regular bolts suffice for a spark gap?

I'm thinking about using MOT power for the low cost and big power. Anyone
have some good info on those? I think it was your site, Gary, that I looked
at that had some good info.

John,

Do you have any pictures of this protection system you have?

Aaron


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, January 07, 2004 11:29 AM
Subject: RE: Some newbie questions


  > Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com>
  >
  >
  >
  >
  >  >Original poster: "Aaron Aab" <striker754-at-earthlink-dot-net>
  >  >
  >  >Hey guys!
  >  >
  >  >Building a coil in my garage, and have a couple questions.
  >  >
  >  >Can I drill a hole in the pvc pipe and run the 2 ends of the secondary
coil
  >  >inside the pipe to a lug in the caps and then use a bolt to exit the
pipe?
  >
  > That's generally a bad idea, as it invites arcing along the interior
  > surface.  But the mechanical benefits of what you propose are
  > tempting.  I'd recommend placing a pair of plastic disks or baffles
inside
  > the pipe just inside the ends of the coil.  Cement them in place using a
  > liberal dose of PCV cement.  Then make the holes so that the two disks
are
  > between them, blocking and arcing.
  >
  >  >Does everything needing to be grounded go to the same ground rod?
Strike
  >  >rod, secondary coil, etc?
  >
  > Yes.
  >
  >  >Are there any cheap protection I can use to protect the NST? I don't
want
  >  >to spend 50 bucks worth of stuff for that one protection circuit. Will
a
  >  >safety gap, and 2 chokes work well? Chokes are just magnet wire wrapped
  >  >about 100 times around a pvc pipe correct?
  >
  > The use of chokes was advocated before folks began simulating and scoping
  > what actually happens.  Don't use them, they cause more problems than
they
  > solve.  Instead use R-C filters.  Two 1000 pf 10kV ceramic disk caps in
  > series ($1 each) between each NST HV bushing to the case, and a 1K 50W
wire
  > wound resistor from each bushing to the main spark gap.  And a safety gap
  > from each HV bushing to case.
  >
  >  >
  >  >Thanks a bunch!
  >  >
  >  >Aaron
  >
  > Regards, Gary Lau
  > MA, USA
  >
  >