TSSP: List Archives

From: "Barton B. Anderson"
Date: Wed, 22 May 2002 23:54:34 +0000
Subject: Re: [TSSP] Topload breakout potentials

Hi Paul,

Paul wrote:

> I'm not too worried about the error in k, but that
> apparent shift in Cpri needs accounting for.
>
> Can you confirm that your primary Fres (sec removed) is close to
> 61.4 kHz?   If so, then the 61nF cap is really 66nF and the bang
> energy goes up with it.  Has the cap been measured recently?

Yes. Just made both measurements.
Fres (sec removed) measured 61.6kHz tonight. The cap measured 65nF tonight.
I made the cap measurement connected and by itself. Connected is 65nF. No
connection toggled between 64 and 65nF finally resting at 65nF. When it's
connected, it could be anywhere between 65nF and 65.9nF, but due to the
number of digits and meter accuracy, I can't identify below 1nF movement.
Since it toggled on the "not connected" measurement, it must be between
64.9 and 65nF.

> The frequency has hardly changed with your new arrangements at the
> coil top, but that high surface field at the top rim of the secondary
> has reduced considerably and it is no longer the 'hottest' spot on
> the sec.

Only a few turns on the bottom were removed and it's a pretty high turn
coil, so I wouldn't expect much of change. The toroid is still at 77" and
the corona ring is swamped by the toroid (however, with the ring, I
expected a noticable change, but that goes to show what I know about carona
rings).

> I've updated ba0 in
>  http://www.abelian.demon.co.uk/tssp/cmod/
>
> with the new settings, but I'm still at the full firing voltage.
> Your tuning is at about -12%.

I calc'd about 9% a day or two ago. Oddly, I measured the cap that day at
61nF. Today I'm getting a difference. Maybe I should begin taking daily
readings? I don't like the fact that it's changing (9 to 12% is rather
significant). I guess I better use 2 different meters.

> > strike rod about 4 feet from edge of toroid
> > placed a breakout point on the toroid
>
> When you go back to a smooth toroid, no breakout point, and no strike
> rail, does the tuning remain the same?  I guess that's the hard one
> to do inside the garage!  It would be interesting to know at what
> variac setting the smooth topload is just breaking out.

I don't notice a change in tuning (there may be some slight difference, but
doubt I could tell).

I should be free to run it tomorrow night. I could take inductance
measurements of the variac if that is helpful, and then do the same with
the breakout point. I'm still shopping for a current meter (although, maybe
I could bring home a clamp meter. That would probably suffice for now).

Take care,
Bart


Maintainer Paul Nicholson, paul@abelian.demon.co.uk.