RE: Hot Primary

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

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

OK, I was afraid you might have been running a pig through a 22 gauge
primary or something silly like that, but things look for the most part
pretty reasonable.  The one thing I note is that your primary is a fairly
low inductance with only three turns.  This is bad on several fronts:

1) Low inductance primaries result in higher losses in the spark gap.
2) Pri-sec coupling may be lower than optimal.
3) Low inductance primaries result in higher resonant frequencies, and
higher frequencies result in higher resistive losses in conductors.  This
means the primary may run hotter.

When you said you have to run a lot of topload, how much do you have?  More
is generally better.  Increasing it further would lower the frequency and
make you use more of your primary; that's what I would try.

Regards, Gary Lau
MA, USA


Original poster: "Gregg Adams by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<network-at-nexband-dot-com>

To all who responded to my question, thanks and here's the specs on my coil:

Secondary: 4.25" / 22 gauge / 22 inches in length
Primary:  flat sprial / .25inch copper tubing / tapped at 3rd round out
Power supply:  dual MOT's with voltage doubler(12kv) / not sure on the
amprege
Tank cap:  .05uf -at- 12kv / 2 strings of 6 geek caps(.15uf -at- 2kv) I have more
just not hooked up.
Spark gap:  ARSG / 10k rpm angle grinder w/6 inch disc and 4 contacts
Performance: 40+ inches

My primary is getting hot enough that you can't leave your hand on it for
more than a few seconds.  Also, I'm having to run alot of topload now.





----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, July 02, 2002 9:53 PM
Subject: RE: Hot Primary


> Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Gary.Lau-at-hp-dot-com>
>
> It depends.  What exactly is your primary made out of and what is your
> power supply?
>
> Gary Lau
> MA, USA
>
>  -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Tuesday, July 02, 2002 3:05 PM
> To: tesla-at-pupman-dot-com
> Subject: Hot Primary
>
> Original poster: "Gregg Adams by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <network-at-nexband-dot-com>
>
> Hey all,
>    What would be the cause and cure for a primary getting hot?