From: futuret@xxxxxxx <futuret@xxxxxxx>
Subject: Re: [TCML] New 833C VTTC - poor performance
To: tesla@xxxxxxxxxx
Date: Saturday, August 2, 2008, 1:07 PM
Kris,
You have to retune the primary as you increase the power
and as the sparks get longer.? A primary tune point
that's best
for a 10" spark, will be the wrong tune point for a
20" spark.
This is because the length of the spark acts as an extra
capacitor and changes the resonant frequency of the
secondary
while the spark is being produced.? You'll need to tune
outward
on the primary, (use more turns), as the sparks get longer.
This is most likely the problem you're having since I
can't think
of any other good reason for the weak sparks and red tube
plate
you're seeing.?
20 turns on the grid coil is probably OK.? You can try
tapping
off at 16 turns or so, but I doubt it will help.
Cheers,
John
-----Original Message-----
From: Kris Grillo <kristianisawesome@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Fri, 1 Aug 2008 8:03 pm
Subject: Re: [TCML] New 833C VTTC - poor performance
John, list,
"I assume you have a breakout point above the toroid
(about 4 to
5" tall or so maybe)"
I do have a breakout that extends 4" above the toroid.
"You have to tune at full power. If you tune at low
power, the tune point will
be wrong at high power."
I'm not sure what you mean by full power. I brought the
variac up slowly until I
noticed the plate glow, then I backed down a tad and made
adjustments. I
repeated this process for hours. Once I got the primary
dialed in, I didn't mess
with it at all. The power input couldn't change the
frequency, could it?
"I assume your caps can handle the power? Are they
getting hot?"
As far as I know, they can handle the power. They are the
TDK UHV-9A 202K 40KV.
One for the tank and one for the grid leak. They were on
again off again for
quite a while and they do not even get warm as far as I
could tell from
occasional touch testing.
"Also if you have an 833A, you can try that."
I don't have one.
"You can try using a higher grid resistance too. Just
put another resistor in
series with the one you have."
I don't have an appropriate resistor on hand for this,
but I will pick one up
and give it a try.
Could 20 turns of #26 be yet to many turns for the feedback
coil?
Thanks,
Kris