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Re: [TCML] Fairly big changes to my little 304 VTTC

It seems to me that If the coil is running at a low break rate, the average current should be much lower than when running at a high break rate.  I agree that the peak current or current during the "on time" will be similar at both high or low break rates.  
I think the scope is looking at peak current, or calculating RMS current during the "on time", so it's not showing the average current.  
If you make the VTTC pulse ten times slower, I'd expect the average current to be about 10 times lessalso.  If it draws 10 amps at 60 pps, then I'd expect it to draw about 1 amp average at 6 pulses per second.  But the analog meter might not read accurately under pulsed conditions.  
I'd expect the MOT transformer to stay very cool during low pulse rate operation also, due to the low average current.  You'd have to start with the MOT cool, then run at the low break rate and see how long it takes for the MOT to warm up.  Then compare this by starting with the MOT cool, then run at a high break rate and see how long it takes for the MOT to warm up.  It should warm much faster at the high break rate.   
I seem to remember my own staccato VTTC's behaving the way I describe above.  But my memory is hazy.   
Also the vacuum tube plate should run very cool at the low break rate, but run hot at the high break rates.  My VTTC's definitely worked that way.  

-----Original Message-----
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Mon, Dec 16, 2019 8:16 am
Subject: Re: [TCML] Fairly big changes to my little 304 VTTC

Hi all and John,

Just a quick post here, bouncing from the EVR interrupter thread. In the
process of figuring out and fixing the couple of things on the EVR, a
subject came up about my analog current meter readings. And I felt it was
more appropriate here because of the changes made here. I have had a
current clamp for my scope for quite a while now and had yet to try it out.
So I got it out to compare to my cheap "utility" amp meter on the line
power cord.
Well it turns out it seems to be fairly accurate as I thought, as I have
said before I have also just made a judgement call just by feel/touching
the MOT checking it's temperature.
So I think they both are accurate enough for what I am doing here out of


In this first link, I have put on a different constant steady load to check
analog meter and clamp. Again this is not the coil. As seen in the pictures
you can see they agree pretty close. The current clamp setting I was using
here, the Vrms of 104 mV converts to 10.4 Arms. As seen, analog meter
showing 10.5


In the second link here, I am running the coil at it's lowest break rate. I
knew the peak line currents are much higher, so before hand I changed the
clamp setting.
Here once again, you can see they agree. The Vrms of 12.0 mV converts to
12 Arms. Analog showing 12

Note the peak current. I knew much higher, but did not know what
approximately. So I found this interesting myself. I have never done these
kinds of checks on input line current ever before.

So I also have been just "playing around" also here with the current clamp,
varying break rates and the time base on the scope. Can see several
different interesting things and also still trying to decide if some things
are possibly caused by noise in what I am seeing. Have not decided yet. So
come next weekend probably, I will do some more and may take pictures
and/or video of some things I am not sure about and post here that puzzles
me some...

Hopefully I fixed all my typos and said everything correctly here :^)

Chris Reeland
Ladd Illinois USA

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