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Re: [TCML] Some VTTC tube rolling results...got surprised twice!

Hi Chris,

Interesting work with the tubes Chris. I haven't done anything more to my 833A coil. I got stuck at 20" which is perfectly acceptable to me. I think my limitation is my MOT. About all I can get out of it is 16 amps at the MOT input. I tried the one other MOT that I have from a 1970s Amana Radarange that is bigger. It has about 50% more iron in it. Indeed with this bigger MOT I could pull about 20 amps. For some reason though it yielded very broken streamers. I didn't really feel like investigating it further at the time so I went back to the original MOT. So I think where I stand is that if I want longer streamers I am going to need a beefier transformer or 2 MOTS in parallel. The problem with that is that my current VTTC weighs about 70 pounds and is still sort of transportable. Installing a heavier transformer will make it even less transportable. Since one of my goals was to have a self-contained portable VTTC to take to schools and such, making it heavier is not very attractive. I am now in the middle of building a Marx generator but eventually I will get back to the VTTC. You can see some pictures of my VTTC from the 2018 Ohio Teslafest at this link:


There is one really cool picture of it in operation with the lights out. The interior is lit with the blue LED on the back of my interrupter card. The top is lit by the 833A filament. The front panel is lit by the 2 red pilot lamps. I also have my ion engine installed on the discharge point which creates the purple streamers. So the picture ends up with yellow, purple, blue, and red colors in it. I didn't take the picture.

Steve White
Cedar Rapids, Iowa

----- Original Message -----
From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Thursday, September 6, 2018 4:44:00 AM
Subject: [TCML] Some VTTC tube rolling results...got surprised twice!

Hi all,

This past weekend I rolled a total of 12 tubes on my normally T-200 tube
MOT VTTC which has several postings on here in the past. This is just some
brief results of all tubes from my notes. This rolling was mainly to test
several tubes that I have aquired recently and several that I have had for
quite a while and never have gotten around to trying. And just to have fun
seeing streamers, which has been a while since starting a new job. Just
been too busy, which I think I mentioned on a different thread post here.

#1 Starting with the normal Cetron T-200 to verify all is still running the
same. Got the expected 31" as usual.

#2 Penta Lab.  PL-254W  Got 23" with this tube which is about what I
expected, this is not a very powerful tube, but it did great for what it is.

#3 Eimac 450TL  Got 18". Disappointed that this tube is weak. There was
some strange uneven heating of the plate, so that explains why.

#4 Eimac 450TH Got 31". Which is about what was expected.

#5 Eimac 6C21 No.1 Got 31" (same as above)

#6 Eimac 6C21 No. 2 Got 31" (same)

#7 Eimac 6C21 No. 3 Got 31" (same)

#8 Eimac 1000T Got 31" (same) Also, this big fella hardly breaks a sweat

#9 Eimac 304TL No. 1 Got 31", but got perfect "Swords"! Just one after
another, which I also mentioned the other day in a different post thread.
(When posted, I had yet to try the tubes below on list.) Surprised by this.
Still somewhat puzzled by this fella. Always got just sword like and not
consistent always at that on this coil. Here is a picture link again for


#10 Eimac 304TL No. 2 Got 36"+!!! Surprised!!! Need something longer to
measure with now! Yardstick surpassed now :-) These are the typical sword
like and not consistent as usual, but now crazy long for this little coil.
For those that don't know, I will give a couple of quick details of the
coil: The secondary is just 2"dia. by 13.75" of No.28 wire. Primary wire is
just No.14 neon sign wire. Still puzzled some here again. Did not see this
coming at all! Thrilled of course though! Here is a picture:


#11 Eimac 304TH No.1 Got 36"+ again!!!
(same as just above) Something about these tubes that my coil really likes!

#12 Eimac 304TH No.2 Got nothing. Got a dud. Just one bright, two dull, and
one completely out filament. Did not bring up to full filament voltage
because of this. And of course no plate voltage at all. Even though the
filaments on the tube pins check okay with basic meter checks, I always
bring them up slowly, watching carefully. Good also to limit inrush current

So just 2 bad tubes of the bunch.
But surprised 2 times (well maybe 3, depending on how you look at it).

So this weekend, I am going to do more testing of these 304's and some
measurements also hopefully. Going to go back to some of the other tubes
also and try a few things.

Okay enough for now... just might have to rename my coil to a 304 now. We
will see, after some more testing this weekend to reverify.

Chris Reeland
Ladd, Illinois, USA

Oh, just one more thing, specifically to Steve White. Have you done
anything to your 833A coil in the past several months, since we last had an
Just wondering.

Sent from my LG V20
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