Hi Chris,
Maybe the changes you made to the primary and cap are reducing the amount of grid feedback and thereby reducing the current draw? Also maybe your tuning is a little different now, also affecting the current draw?
In experiments I did with changing the ratio of primaryinductance to tank C, it never seemed to make muchdifference to the overall performance. But I didn't reallydo many such comparisons.
If the EVR board is mis-firing and firing late in the 60Hz AC cycle, that could be reducing the current draw too (but it would have to be quite late to make much difference). Or maybe some firings/triggerings are being skipped completely?
In some of my staccato work, I used to get occasional misfirings (I could hear it), the pulse would sound softer and the spark shorter and more likely to branch. There would also be a sharper "snap" sound on some pulses, rather than the solid "thud" sound I never did figure out what was happening in those cases. Or if I did, I don't remember. In any case it reminded me very much of the weakerfirings I'm seeing with your EVR board.
VTTC's seem to be tricky beasts.... :^). I like the way you're thinking everything through carefully, thoroughly, etc.
John
-----Original Message-----
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Wed, Oct 23, 2019 8:48 am
Subject: Re: [TCML] Eastern Voltage Research VTTC Staccato Controller - puzzled on "burst" output
Hi and Thanks, John.
Yes, my gut feeling is this is related to the trigger pulse also. I have
looked at my before scope traces, before I rebuilt the "breadboard"
interrupter, and this is what I see. But I want to check it's current state
to verify, so come this weekend...Too busy during the work week at my job.
I will post some side by side pictures. I think I am going to study the EVR
schematic and try fixing this when I can.
Glad you have further explained the reason for the bypass switch.
Completely understand why now. On the scope in the past, I have
experimented on my "breadboard" one, "playing" with the trigger pulse
wider. I also wanted to get better understanding of what was going on. And
now I do remember, not being able to do 60pps. And well, at least for me, I
had some stability problems also, so I backed off. I never did with the
extra wide, actually try running on coil. I think I am going to revisit
this again.
The burst mode is definitely interesting.
I have never seen this before myself. I have watched all kinds of VTTC
videos on the web and on YouTube and have not seen this. I like to study
these videos, in what I can see, try to get ideas and learn if I can. Of
course a lot are poorly shot unfortunately. Hmm...that does sound
interesting if you could space this as you said. Should be greater streamer
length also. But still neat as is, but you also have me thinking though...
I am still not completely sure what to make of my current readings, burst
or even just regular 1 pulse. Ever since my changes to the primary and cap
I see this happening. Starts at an amperage, bring rate up a little, goes
down some, then as rate goes up more, then starts climbing again, but not a
great amount. Before with original primary and cap, pretty much did as you
say, and for me the amp draw got very considerable, so could not run very
long at all at higher rates. Now I can run fairly high rates non-stop.
Confirmed because MOT is just warm, agreeing with what I see on the meter.
Have you seen my other thread on this?
[Fairly big changes to my little 304 VTTC]
Have more details here.
Also, I want to make a comment on the sounds of the burst. My old unused
smartphone that I am using to take the video, does not have the best
microphone. You might have noticed the volume change in each video at a
certain point. Does it every time once the sound level gets to a certain
point. And the sound does not do it full justice as in person.
But since I will have the scope out anyways, I am now going to look at the
120 line current on my scope to see if my meter agrees fairly close. Also
curious of what the actual peaks look like also.
Related to this, not too long ago, I picked up a Pearson current monitor
for the scope with a wide frequency range.
Just recently got a cable for it. Been meaning to try it on the Secondary.
Now especially curious on what is going on during burst mode.
Okay, enough for now...I can keep going here :^) I think I covered most
things here. You have helped me in a good way... thinking of several other
things now also to try... Thanks.
Pics coming sometime this weekend. Maybe some more video also.
Chris Reeland
Ladd Illinois USA
Sent from my LG V20
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