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RE: Building A VTTC
Original poster: "Cameron B. Prince" <cplists@xxxxxxxxxx>
Hi Henry,
Thanks for your kind comments... Here is a recent photo of the 36"
discharge:
http://www.teslauniverse.com/members/cprince/images/vttc/DSC00152.JPG
It is very difficult to coerce the coil into hitting the 36" mark and not
trip the 20A breaker. I believe 34" is really the consistent top mark for
the coil within the operating parameters I've set.
I am going to build the updated staccato controller this weekend hopefully
and experiment with the display.
I'll let you all know how it goes.
Thanks,
Cameron
> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Thursday, August 24, 2006 11:03 PM
> To: tesla@xxxxxxxxxx
> Subject: RE: Building A VTTC
>
> Original poster: "Henry Hurrass" <Dr.Hankenstein@xxxxxxxxxxxxx>
>
> No problem, Cameron.
>
> I understand what you are trying to accomplish and I agree by all means
> that the only way get there is by doing the actual experiment; as Nikola
> Tesla once said: "The work is not complete until the experiment has been
> done."
>
> Your recent work has put the "Armchair Coiler's Group" to shame! Keep up
> the good work!
>
> Cheers,
> Dr.Hankenstein
>
>
> > [Original Message]
> > From: Tesla list <tesla@xxxxxxxxxx>
> > To: <tesla@xxxxxxxxxx>
> > Date: 8/23/2006 12:15:52 PM
> > Subject: RE: Building A VTTC
> >
> > Original poster: "Cameron B. Prince" <cplists@xxxxxxxxxx>
> >
> > Hi Henry,
> >
> > Thanks for your comments and I wholeheartedly agree... However, I think
> you
> > guys are somewhat missing the reason I suggested the counter display.
> In
> my
> > tuning one thing that has consistently been a difficulty is reproducing
> the
> > same environment with different components. Having a display would
> allow
> me
> > to know that I am back to a certain point I was before or allow me to
> > document where I am currently with a particular result. It's a metric.
> >
> > I am using my senses now and tick marks around the knobs, but those
> only
> go
> > so far. I have an isolation transformer and HV probe on the way so I
> can
> do
> > some measurements with the scope, but having a display built-in to the
> panel
> > would be ideal. Let's not fail to consider the coolness factor too. :)
> >
> > Dave Sharpe has been helping me some already and I'm going to start by
> > building the updated controller circuit he helped Dan design at:
> > http://www.easternvoltageresearch.com
> >
> > Once I have it going I plan to try and integrate the counter display.
> It's
> > only a small number of components and shouldn't be a big deal to build
> on
> a
> > breadboard.
> >
> > Thanks again for you comments,
> >
> > Cameron
> >
> >
> >
> > > -----Original Message-----
> > > From: Tesla list [mailto:tesla@xxxxxxxxxx]
> > > Sent: Wednesday, August 23, 2006 7:51 AM
> > > To: tesla@xxxxxxxxxx
> > > Subject: Re: Building A VTTC
> > >
> > > Original poster: "Henry Hurrass" <Dr.Hankenstein@xxxxxxxxxxxxx>
> > >
> > > I think the whole idea of the staccato controller in the first place
> is to
> > > limit the "watts dissipation" that the plate really thinks it's
> seeing. As
> > > an example, if you limit the duty cycle to say 50%, you could
> conceivably
> > > double the plate dissipation (thus producing a longer spark), but
> the
> > > "average plate dissipation" would still be below the "max plate
> > > dissipation" allowed for the tube. I.E.: 500W times 50% duty cycle
> equals
> > > 250W avg. = longer spark. Without the staccato controller (which is
> really
> > > only a pulse width or duty cycle controller AKA: CW Mode) the plate
> would
> > > normally melt. I personally do not like to see plates glowing any
> color
> > > other than black for longevity of the tube. Who cares what the BBS
> rate is
> > > as long as you find the sweet spot where you would back-off the duty
> cycle
> > > to make your coil a long time AND a long spark performer. Look at
> the
> > > plate: If it's glowing, you are probably giving too much "hammer".
> enjoy
> > > and BTW nice work!
> > >
> > > regards,
> > > Dr. Hankenstein
> > >
> > >
> > > > [Original Message]
> > > > From: Tesla list <tesla@xxxxxxxxxx>
> > > > To: <tesla@xxxxxxxxxx>
> > > > Date: 8/22/2006 11:39:31 AM
> > > > Subject: Re: Building A VTTC
> > > >
> > > > Original poster: "Steve Ward" <steve.ward@xxxxxxxxx>
> > > >
> > > > Since the pulse rate is always some even division of 60, its
> pretty
> > > > easy to listen to hear the 30, 20, 15, and 10pps. Below that you
> may
> > > > need a counter. Most people have scopes or maybe a meter that
> can
> > > > count, i dont think i would bother putting a counter circuit into
> the
> > > > staccato controller.
> > > >
> > > > Steve
> > > >
> > > > On 8/21/06, Tesla list <tesla@xxxxxxxxxx> wrote:
> > > > >Original poster: "Cameron B. Prince" <cplists@xxxxxxxxxx>
> > > > >
> > > > >
> > > > >Hey guys,
> > > > >
> > > > >I think the consensus is we need some sort of counter to help
> > > determine
> > > the
> > > > >current pulse rate of the staccato controller. John, this is
> what I
> > > had
> > > > >emailed you about a few weeks ago. I think it would be really
> nice
> to
> > > > >incorporate two 7 segment displays into the controller that
> display
> > > current
> > > > >pulses per second. I have briefly looked into this and found the
> > > schematic
> > > > >here:
> > > > >
> > > > >http://martybugs.net/electronics/speedo.cgi
> > > > >
> > > > >It's for a digital speedometer display but I think the concept
> is
> > > about
> > > the
> > > > >same:
> > > > >
> > > > >1) Take a sample
> > > > >2) Perform an average
> > > > >3) Display value
> > > > >4) Return to step 1
> > > > >
> > > > >What are your thoughts on this circuit and adapting it to
> interface
> > > with
> > > the
> > > > >staccato controller? Is there a less complex way or circuit that
> would
> > > > >provide the same results that you know of?
> > > > >
> > > > >Thanks,
> > > > >Cameron
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Tesla list [mailto:tesla@xxxxxxxxxx]
> > > > > > Sent: Monday, August 21, 2006 6:58 PM
> > > > > > To: tesla@xxxxxxxxxx
> > > > > > Subject: Re: Building A VTTC
> > > > > >
> > > > > > Original poster: FutureT@xxxxxxx
> > > > > >
> > > > > > In a message dated 8/21/06 4:07:27 PM Eastern Daylight Time,
> > > > > > tesla@xxxxxxxxxx writes:
> > > > > >
> > > > > > >It seems that you have made a quantum leap in
> > > > > > >the stacatto controlled VTTC that probably hasn't been pa-
> > > > > > >ralleled since the 1990s when John Freau himself first
> intro-
> > > > > > >duced the stacatto controlled VTTC, capitalizing upon the
> > > > > > >higher output from the same power input through the
> > > > > > >priciple of lower duty cycle firing. And I also think that
> it
> > > > > > >should be pointed out to the rest of the list that this is
> your
> > > > > > >very first VTTC project, so basically you've made these
> > > > > > >advances as a VTTC beginner!
> > > > > > >
> > > > > > >Keep up the good work,
> > > > > > >David
> > > > > >
> > > > > >
> > > > > > Cameron, David,
> > > > > >
> > > > > > Yes, Cameron has obtained very impressive results from his
> > > > > > VTTC project.
> > > > > >
> > > > > > My original coil that gave the 36" sparks, and later
> > > > > > the one that gave 38" sparks didn't have a staccato system
> > > > > > attached, so they ran at 60 PPS, and drew a lot of power.
> > > > > > These early designs were unable to give the straight sword-
> like
> > > > > > sparks, so the sparks tended to get a lot shorter when the
> > > > > > staccato feature was added. I did at some point add the
> > > > > > staccato feature but the sparks got shorter when the
> staccato
> > > > > > was operating.
> > > > > >
> > > > > > One of my early coils gave the sword-like sparks. In this
> > > > > > coil the spark length did not decrease in the staccato mode.
> > > > > > I could reduce the pulse rate to 1 pulse per minute, and the
> > > > > > sparks remained just as long. But this was a smaller coil
> > > > > > which produced 20" sparks from a single 4-250A tube
> > > > > >
> > > > > > When I added the staccato system to my coils in general
> > > > > > I didn't go back to modify the coils to take advantage of
> the
> > > > > > staccato features, so the sparks didn't get any longer, the
> > > > > > input power simply decreased.
> > > > > >
> > > > > > When I had spoken to
> > > > > > Steve Ward and others, I suggested that they modify their
> coils
> > > > > > (compared to mine) by lowering the plate impedance to take
> > > > > > advantage of the staccato capabilities. This is what I was
> > > planning
> > > > > > to do but I got involved in other work. Also around that
> time
> I
> > > had
> > > > > > introduced the zero-crossing staccato circuit which helped a
> lot
> > > for
> > > > > > staccato stability. I sent this schematic to Steve Ward and
> he
> > > > > > incorporated it into his coil and placed the schematic at
> his
> > > > > > website. He did optimize his coils to take advantage of the
> > > > > > staccato, by lowering the plate impedance. Cameron has
> > > > > > done that also.
> > > > > >
> > > > > > Some later coils that I built did give the sword-like
> > > > > > sparks, so they were able to maintain their spark lengths
> > > > > > while running at a slower staccato pulse rate. One later
> design
> > > > > > coil (circa Feb, 2001) produced 24" swordlike sparks in the
> > > > > > staccato mode and also without staccato. This coil used two
> > > > > > 833A tubes and was capable of running without staccato
> > > > > > without overheating the tubes. It produced 24" sparks.
> > > > > > When running without staccato it drew 2400 watts while
> > > > > > producing the 24" sparks. By using the staccato, the
> > > > > > power draw could be dramatically reduced depending
> > > > > > on the pulse rate. For example if the coil was run at 30
> PPS,
> > > > > > Then it drew 1200 watts (somewhere around 10amps). If the
> > > > > > coil was run at 15 PPS, then it drew 600 watts (~ 5 amps).
> > > > > >
> > > > > > I use a similar formula to my formula for spark gap coils,
> > > > > > for VTTC's without staccato.
> > > > > >
> > > > > > spark length inches = 0.5*sqrt input watts.
> > > > > >
> > > > > > This formula is for VTTC's which are running at the full 60
> PPS
> > > > > > (no staccato). The coils will of course be much more
> "efficient"
> > > > > > in staccato mode.
> > > > > >
> > > > > > As an example there is my 2nd large VTTC coil which gave the
> > > > > > 36" sparks at around 5500 watts. So if we take the sqrt of
> > > > > > 5500 = 74.16. Then multiplying this by 0.5 gives 37" which
> is
> > > > > > very close to the 36" I obtained. I think I turned up the
> power
> > > > > > a little higher to get the 38" which I eventually obtained.
> > > > > >
> > > > > > Now we can do an example with staccato mode. Consider
> > > > > > my coil that gave 24" sparks both in or out of staccato
> mode.
> > > > > >
> > > > > > without staccato:
> > > > > >
> > > > > > 24.49" spark length = 0.5*sqrt 2400 watts
> > > > > >
> > > > > > So it can be seen the formula is quite accurate for this
> coil
> > > also.
> > > > > >
> > > > > > But with staccato at 20 PPS the formula must be modified.
> > > > > >
> > > > > > 24" spark length = 0.76*sqrt 1000 watts
> > > > > >
> > > > > > note I used 1000 watts instead of 800 watts to allow for the
> > > > > > filament power for the two tubes. In some of the calcs here
> > > > > > I didn't bother accounting for filament power.
> > > > > >
> > > > > > At 15 PPS:
> > > > > >
> > > > > > 24" spark length = 0.86*sqrt 800 watts
> > > > > >
> > > > > > I think at some particular slow pulse rate
> > > > > > the spark length diminished some. I'm not sure though.
> > > > > > If the staccato pulse rate
> > > > > > is very slow, the spark will not appear continuous but will
> > > > > > appear pulsed when viewed by eye. When speaking about
> > > > > > the efficiency of a staccato tube coil, it's best to give
> the
> > > > > > staccato pulse rate because the pulse rate has such a
> > > > > > dramatic effect on the power draw. When the coil runs
> > > > > > at 30 PPS, the sparks look almost as full as at 60 PPS.
> > > > > > At 20 PPS the sparks look good too. Each pulse rate
> > > > > > has it's own interesting appearance and sound. When
> > > > > > the rate gets slow enough, down to 15 PPS or so, only
> > > > > > a single sword like spark will be seen. This sword spark
> > > > > > will waver back and forth slightly as the coil runs. This
> > > > > > type of spark can be seen at my website, as well as
> > > > > > other types of sparks.
> > > > > >
> > > > > > Basically if you optimize the VTTC for staccato, then it
> will
> > > > > > not be able to run continuously without staccato. The tubes
> > > > > > will overheat. So there's a tradeoff. Either use a high
> plate
> > > > > > impedance and permit the coil to run at the full 60 PPS
> > > > > > (no staccato), and limit the spark length (even with
> staccato
> > > > > > turned on). Or use a lower plate impedance and only
> > > > > > run in the staccato mode at 30 PPS or less to prevent the
> > > > > > tube from burning up. But longer sparks will be obtained.
> > > > > > The coil can be turned up to full power without staccato
> > > > > > for short durations, but not continuously. Keep an eye
> > > > > > on the tube plate and watch for excessive redness. Turn
> > > > > > down the power very quickly as needed.
> > > > > >
> > > > > > John
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> >