RE: Primary cap

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>

>Original poster: "Johnson, Jeffrey D -at- PWC by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jeffrey.d.johnson-at-l->3com-dot-com>
>
>Hi,
>I've seen two configurations for the TC primary: 1) spark gap across
the nst
>secondary with TC primary cap in series with TC primary to the right of
SG,
>2) cap across nst secondary, followed by SG in series.  Is one better
than
>the other.  I read that having the SG in parallel provides a safety gap
at
>the same time.  

I agree with Terry's advice to put the spark gap across the NST
secondary.

>Should the primary cap be matched to the nst secondary?
>Only if it's in parallel?  If in series, do you not worry about
matching the
>nst secondary impedance?  

The cap/NST matching is unaffected by the choice of cap/gap
configuration.

>One last question.  I've seen some stuff about LTR
>caps.  Are these used to keep from having 60Hz resonance with the nst?
Many
>concepts in need of tying together here.
>Thanks....
>
>JJ - slc

Minimizing 60 Hz resonant rise is one reason that LTR cap-sizing is
used, although if gaps are properly gapped (static) or phased (rotary,
again, easier said than done!), resonant rise should not be an issue.
But I've also found that aside from minizing mains-resonance (a bad
thing), there is nothing special about this, and I've found best
performance at about 2X mains-resonance cap value.

Regards, Gary Lau
MA, USA