Re: Staccato coil operational- Thanks y'all

[cwillis-at-guilford.edu (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Actually what was happening with my flashover was a wiring problem:  I left out
a resistor in the AC phase in divider!  Got that fixed, and I still get
basically the same operation but without the flashover.  I don't seem to get
the "swordlike" spark that you describe, John, but rather I am still getting a
brush with a few branches, like four or five.  I have a point on the side of
the bottom of the toroid that spits them out, and while the brush remains
pretty insubstantial, I get thick, long sparks to my hand.  One interesting
thing about the sparks is that when the pulse rate is about 5 or so per second,
I can see little ~5-mm "knots" in the spark, like little loops or beads that
are wider and more orangy than the rest of the channel.  I'd like to try to
make some photos of the single-burst sparks.

And I spoke too early about the tube not getting to me, since it got here
today.  The guy's not a fraud, just a little slow on his end since I ordered it
on Aug. 22 (and I'm sure the mailroom was slow on this end also.)  When it
comes to coil parts getting here promptly, I'm more impatient than usual and
I'm sure that feeling is shared!  

Anyway, I have been considering two more 833A purchases-  four RCA tubes with
light or no use, with sockets, at $50 each, and two more new chinese 833A's for
$40 each.  The reason I mention this is that I don't need all these tubes
myself but have to buy the available quantities to get any of them, and if
anyone else has interest in such a tube let me know.

-Carl



-at-
Sent by: "Tesla list" <tesla-at-pupman-dot-com>
09/13/2000 11:29 AM CST

To: tesla-at-pupman-dot-com
cc: 
bcc: 
Subject: Re: Staccato coil operational- Thanks y'all


Original poster: FutureT-at-aol-dot-com

In a message dated 9/12/00 9:52:23 PM Pacific Daylight Time, tesla-at-pupman-dot-com
writes:

> cwillis-at-guilford.edu
>
>
>  Greetings Tube coilers, and thanks to Dave and John, etc. for helping me
>  come up to speed with my tube coiling.

Hi Carl,

Thanks for the update on your staccato coil.  Those super
controllers would be most interesting to try.

That's really rotten about the new tube deal.  The guy is really a crook
then....there's no hope he'll ever send the tube?   Maybe a precise
phase adjustment might help prevent the flashovers?

John Freau
--

>
>  I just finished building a staccato controller for my coil per Dave
>  Sharpe's design, and it was working flawlessly on the first run:  "pop pop
>  pop pop..." The discharge makes a very satisfying sound and spark frequency
>  can be changed from 30 per sec to about 1 per sec.  I am using an SCR that
>  is rated at 600 VRRM and 25 A from Digi-Key that has the advantage of
>  having an isolated tab (so I can bolt it directly to a grounded enclosure
>  for heatsinking.)  I'm only using 9.5 Vcc for the timer circuit, although I
>  know that the timer works better at higher voltage.  I don't have a
>  regulator in the supply but I do have a 5000 microfarad electrolytic cap
>  and a bunch of other bypass caps that give a nearly ripple-free 9.5 volts
>  as far as I can tell with a pair of headphones (you make do with what you
>  have :>)
>
>  Finding the right phase for the staccato triggering was pretty easy.
>  Although the coil will generate a small spark with either phase driving the
>  staccato (probably due to the charged up bypass capacitor) when the power
>  is increased the coil won't operate at all if the phase is wrong.  I have
>  both my staccato and my filament transformer on the same power cord, and if
>  the phase is wrong I just plug the cord in the other way around.
>
>  I still need to look at the operation on a 'scope and set the timing pot on
>  the 556 schmidt trigger properly.  But Dave is certainly right that this
>  timing control doesn't do a whole lot for the trigger.  I can turn the pot
>  from one end to the other and I still get nice staccato operation.   The
>  monostable timing pot gives from about 1 pulse per sec to 30.  I'd like to
>  try some potential ideas for a "super staccato" controller, including
>  converting the monostable timer into an astable timer, allowing the user to
>  adjust how many pulses in a "burst" and how many bursts per second.  Dave I
>  think is working on a "super staccato" controller that allows the user to
>  do this also but I'm not sure how he plans to effect it yet- let me know
>  what you figure out, Dave!
>
>  My present 833A is an older one and so I still have the occasional problem
>  with a flashover.  Unfortunately the fella I just ordered a new one from
>  ran with my money and won't send the tube...maddening!
>
>  -Carl