RE: question

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

Original poster: "David Thomson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>

Hi Godfrey,

I fully understand what you mean by the Potential Transformer is not current
limited.  I put it on my Tesla coil today.  The spark gap looked more like
an arc welder.  My single thoriated tungsten, magnetically quenched, static
spark gap just couldn't handle it.  I've been working all day to build a
spark gap to handle the power.  Fortunately I have eight heavy duty military
electrical contacts made with pure silver rings and some kind of
non-corrosive, hard electrode.  A preliminary test with this new spark gap
on my 15KV NST showed a 100% increase in spark length on my secondary
terminal.

Yes, the impulse level does seem a bit low compared to others I have seen.
But I don't intend to see anything over 50KV in the primary so that should
be OK.  I'm hopeful that this higher current can be put to good use in my
coils.

Tell me some safety tips concerning the secondary terminal when the amperage
is increased.  I haven't worked with a high current transformer on a Tesla
coil before.  Will it still be safe to hold a fluorescent tube to the
terminal to draw off sparks?

Thanks,

Dave

David Thomson
dave-at-volantis-dot-org <mailto:dave-at-volantis-dot-org>


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, January 31, 2002 5:58 PM
To: tesla-at-pupman-dot-com
Subject: RE: question


Original poster: "Loudner, Godfrey by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>

Hi David

My mistake that I thought you were writing about a primary. You certainly
have a potential transformer, not a neon sign transformer. A potential
transformer is not current limited, but a NST is current limited. A
potential transformer is used to monitor the voltage level of a transmission
line. High voltage is reduced to low voltage for connection with a volt
meter. The 50kV peak could mean that the insulation can withstand a
momentary transient of 50kV. Seems a little odd, usually the impulse level
is 150kV.

Godfery Loudner
> -----Original Message-----
> From:	Tesla list [SMTP:tesla-at-pupman-dot-com]
> Sent:	Thursday, January 31, 2002 8:18 AM
> To:	tesla-at-pupman-dot-com
> Subject:	RE: question
>
> Original poster: "David Thomson by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>
>
> Hi Godfrey,
>
> >In your original mailing, you wrote like you were talking about the
> secondary. But a secondary is not flat,
>
> Mine is.  I wound a 27" diameter flat spiral secondary out of 21 gage
> wire.
> I'm doing several experiments with flat spiral secondaries.  You can see
> some of my work with smaller flat spirals wound with three parallel wires
> at
> my web site www.tesla-coil-builder-dot-com.
>
> >What you call a potential transformer just might be a high voltage
> testing
> transformer.
>
> I'm learning a bit more about this transformer today.  I may have been
> wrong
> in stating it was DC output.  The transformer schematic on the cover shows
> a
> positive and negative terminal with arrows supposedly indicating the
> direction of current.  But this may simply mean that one terminal is
> intended to be on the ground side and the output may be AC after all.
> It's
> an older transformer made by Westinghouse and I have much to learn about
> it.
> One person has suggested to me that it is actually an old style neon sign
> transformer.  It has a winding ratio of 120 to 1 and there is nothing
> indicating there is a rectifier inside.
>
> If this is correct, then I have an old 14.4KV neon sign transformer rated
> for 50KV peak.  The label clearly identifies this transformer as a
> Potential
> Transformer.  Perhaps the two are synonymous?  Are there any experts on
> this
> list who can clarify this terminology?
>
> David Thomson
> dave-at-volantis-dot-org <mailto:dave-at-volantis-dot-org>
>
>
>