# 2 VTTC Chris, Dick built his first coil back in '76. Original magazine
plans called for old 5514 triode, but he couldn't find one. So he
substituted the 811A, with a little higher filament transformer. At first,
only got 2" intermittent single brush from top electrode (does not have any
toroid on top). Substituted different cap until he found some old Mica Caps
(Cornell Dublier I think). This pushed the fingerling out to 6"
continuously.
He demonstrated this at the Jaycees meeting, but they weren't impressed by
the tiny little discharge. The WOW came when he had two volunteers from the
audience come up and stand on "dry" wooden chairs. Each was given two
burned-out 4-ft fluorescent tubes (they were shown to the crowd as not
working in a standard light fixture, but other tubes worked-ok.
The volunteers, standing on the chairs, about 8 feet apart and the nearest 6
ft from the VTTC, were instructed to touch the ends of their tubes together
(touching the contacts together) and then touch the free near-ends between
them together - making a 16-ft long light chair and insulated from the
floor. As the tube nearest to the VTTC was turned toward the VTTC, the whole
room lit up when all four tubes burst into brightness - no wires attached
anywhere. Since this went down the center aisle of the meeting hall, several
of the earlier hecklers jumped back in fear of this tiny VTTC.
Used a 1500 volt triad-utrad plate transformer into a 6" primary and a 22"
coil of close wound magnet wire on 2" pvc pipe.
Still have it in the garage, but not been lit up in over 20 years.
Laurie Hoover
-----Original Message-----
From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of
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To: tesla@xxxxxxxxxx
Subject: Tesla Digest, Vol 124, Issue 5
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Today's Topics:
1. VTTC tubes (jhowson4)
2. Re: VTTC tubes (Chris Reeland)
3. Re: VTTC MOT question (Chris Reeland)
4. Re: Mystery Powerstat info needed (Chris Reeland)
5. Re: VTTC tubes (Futuret)
6. Re: VTTC MOT question (Steve White)
7. Re: VTTC MOT question (Chris Reeland)
8. Re: VTTC MOT question (Steve White)
9. Re: VTTC tubes (Chris Reeland)
10. Re: VTTC MOT question (Chris Reeland)
11. Re: VTTC MOT question (dave pierson)
12. Re: VTTC MOT question (Futuret)
13. Re: VTTC tubes (Jay Howson LAST_NAME)
----------------------------------------------------------------------
Message: 1
Date: Sat, 17 Mar 2018 18:35:27 -0400
From: jhowson4 <jhowson4@xxxxxxxxxxx>
To: TCML tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: [TCML] VTTC tubes
Message-ID: <mv09g266gotpv0d0aql8kdrb.1521326006629@xxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Hello all,With all the VTTC talk recwntly, I have been thinking.?
I have a pair of nos amperex 8165/4-65A
tetrodes.?http://www.relltubes.com/products/Electron-Tubes-Vacuum-Devices/Te
trode/4-65A-8165AM.html
What are everyone's opinions regarding usage in a VTTC?
-Jay
Sent from my Verizon 4G LTE Smartphone
------------------------------
Message: 2
Date: Sun, 18 Mar 2018 04:05:43 +0000
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC tubes
Message-ID:
<CAPVCm=PSYE=k1zar-7K-h=3M3zGvBG6QTOwfxKyKi7fiRNd6Lw@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Hi Jay,
After looking at several different data sheets, including another maker of
this tube, these tubes are somewhat similar to an 811A triode, but they have
twice the maximum voltage rating, which is a good thing of course :-) Using
these tetrodes especially in a pair should work pretty good. Since you
already have them, give them a try. Since I am not sure, will this be your
first VTTC? For me they are fun to "play" and "mess" with. Can be especially
challenging to get optimal performance and a long drawn out process time
wise off and on also. But that is what keeps at least for me, interested and
I like the challenge and learning new things tuning them up.
Currently, besides the one that I keep messing with and mentioning here,
that I thought I was done with a while back :-D, Steve and John some how
make me keep messing with it :-D, Dave a bit ago also :-), I have two other
unfinished VTTC's projects going on also.
But overall, they are easy to get going on first light usually for average
performance which as is, is fun to mess with also especially lighting things
up plasma wise.
Chris
Sent from my LG V20
------------------------------
Message: 3
Date: Sun, 18 Mar 2018 04:55:58 +0000
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC MOT question
Message-ID:
<CAPVCm=Mi3gOgv2R+fdsnyUWZsuam7GaLD8+D4jGgxBPn+TfmFg@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Hi Steve,
Um, yes I did start to have problems blowing or tripping the circuit
breaker, after 3 times, had to quit and correct this. It was impossible to
fine tune further. Realized I have now run into a poor power factor problem
at the increased power level now. I will give some more details later on
what I did for this to correct this. So currently I have added about 224uF
in PF caps. Amp draw is now at the current state of tuning, going from 10
amps to 16 amps pulsing. Much better now! Can actually do tuning changes now
no problem.
So if we can eventually find out why your coil is not drawing more amps, you
do need more to get the extra spark length, you may run into this also.
I think you said you are currently at about 15 amps, of course no power
factor correction.
I have not done anything Sat on the coil. I worked very early that day. Was
tired after and need to get other things done.
But I can now try some things tomorrow (Sunday). I hope to give some more
details and pictures.
Also want to say, sounds like the better filament transformer change with
meter and small variac is worth the effort and time. Besides no more surge
problem of course, benefit of being able to manually regulate voltage is a
big plus. I have some line voltage drop from the heavy draw of the coil
running, pulls down filament some. Most tube spec sheets want you to hold
unavoidable fluctuations to a minimum. Typically .3-.4 + or - max. Going low
is worse. You will see where to set it on the plus side so it does not fall
to low. Me when under coil running, I like to keep at +.2 for a slight
safety margin for other possible load conditions.
Chris
Sent from my LG V20
On Sat, Mar 17, 2018, 9:44 AM Steve White <steve.white1@xxxxxxxxx> wrote:
> Hi Chris,
>
> Wow! 23 amps at 140 volts. That is 3.2 KW. I am surprised that your 20
> amp circuit breaker doesn't blow. I guess the slow-blow action of the
> breaker prevents this especially since you are pulsing.
>
> I think my next step will be to replace my home-made filament
> transformer (rewound MOT) with a commercial filament transformer,
> which I now have, and a small variac and voltmeter for filament
> voltage adjustment. It won't make my sparks any longer but it will be
> much more efficient. My MOT-based filament transformer draws about 750
> watts! It gets quite warm even with a cooling fan. I measured the
> commercial filament transformer under load and it only draws about 120
watts and stays completely cool.
>
> Steve
>
> ----- Original Message -----
> From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Friday, March 16, 2018 3:30:07 PM
> Subject: Re: [TCML] VTTC MOT question
>
> Hi Steve,
>
> Yes, I am back to my bigger copper tube toroid again. I have said in
> the past recently that I always find myself going larger especially if
pulsing.
> I tried 4 other smaller sizes working back up to this. I have several
> more going bigger, but of course they get too physically big for the
> size of this coil, and then I would run into frequency problems again,
> which I want to also say if you are considering larger, you may want
> to figure out if you are going to have a possible frequency problem of
pulling it too low.
> This is why I rewound my secondary for a higher starting frequency. I
> have alot more "headroom" to try various changes.
>
> Yeah, having the feedback above a fairly tall primary can have some
> problems. I have mentioned this also in the past. You got lucky you
> caught is soon enough and have taken corrective action, I have seen
> variations of what you said you did to prevent this.
>
> Me, I have stopped a while ago of the "traditional" above the primary.
> I always put it below now. Me, I feel (and some may disagree with me,
> which is ok) that even though in theory, it is only supposed to be
> affected by the primary, it seems to be affected by the higher voltage
> built up on the secondary on the upper end, which happens when you have a
taller primary.
> If a short traditional primary, it is ok above.
>
> At the bottom below the primary, you are of course located at the
> bottom of the secondary, which is mostly current of course, and also
> has the benefit of eliminating high voltage short arcs between the
feedback and secondary.
> I would also say this is much healthier for the grid wire of the tube
> to eliminate this from happening.
>
> I will have more details on this later, but I "was" peaking during the
> pulses about 23+ amps at "140" 100% variac input.
>
> I have not yet done any changes yet last night or today yet. Kind of
> taking it easy...was tired from work. Going to mess around a bit later I
think.
>
> I should be able to give more details and comments and pictures this
> weekend sometime.
>
> Chris
>
> Sent from my LG V20
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
------------------------------
Message: 4
Date: Sun, 18 Mar 2018 05:16:26 +0000
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] Mystery Powerstat info needed
Message-ID:
<CAPVCm=PQzjUx2W-F1=7hL=9EGOD4=Jgxpb72q=4K1h9wQK+k6w@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Hi Steve,
I could not find anything online either and nothing either in some catalogs
that I have.
I think your guess of a lower voltage range is correct. Made for some custom
applications. I'm guessing must of had a tag fall off. I have seen tags on
some small ones, instead of better markings elsewhere on it. In the past
recently, at some Hamfests, I have seen a few odd ball variacs that where
clearly marked on the name plate being lower voltage. Bigger wire also, if
my memory is correct. Usually, all the high frequency variacs that I have
seen are much smaller, usually "color coded" so you know at a glance,
besides usual nameplate markings.
If nobody else chimes in, let me know what it puts out when and if you test
it. Kind of curious.
Chris
Sent from my LG V20
On Sat, Mar 17, 2018, 9:44 AM Steve White <steve.white1@xxxxxxxxx> wrote:
> I have a small vintage Superior Electric Powerstat for which I am
> seeking data. I have searched the internet to no avail. The model
> number is 10-1095. It is the same size as the current model 10 series
> Powerstats. I have some other model 10 Powerstats that I know are 120
> volt. This model
> 10-1095 has far fewer windings and much thicker wire. Because of that,
> I think it must be less than 120 volts. It might be 40 volts or 28
> volts. It weighs about the same as the current model 10 Powerstats,
> possibly a little less. Might it be for 400 Hz operation?
>
> If anyone knows anything about this mystery Powerstat, I would like to
> hear about it.
>
> Steve
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
------------------------------
Message: 5
Date: Sun, 18 Mar 2018 09:44:27 -0400
From: Futuret <futuret@xxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] VTTC tubes
Message-ID: <162395ab121-1de0-cbbb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Jay,
Using a single 4-125A, I obtained a 10" spark if I remember correctly.
Using your two 4-65A's you might get the same spark length I suppose.
Personally I prefer more powerful tubes for a VTTC.
John
-----Original Message-----
From: jhowson4 <jhowson4@xxxxxxxxxxx>
To: TCML tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sat, Mar 17, 2018 10:31 pm
Subject: [TCML] VTTC tubes
Hello all,With all the VTTC talk recwntly, I have been thinking. I have a
pair of nos amperex 8165/4-65A tetrodes.
http://www.relltubes.com/products/Electron-Tubes-Vacuum-Devices/Tetrode/4-65
A-8165AM.htmlWhat are everyone's opinions regarding usage in a VTTC?-JaySent
from my Verizon 4G LTE Smartphone
------------------------------
Message: 6
Date: Sun, 18 Mar 2018 00:39:18 -0400 (EDT)
From: Steve White <steve.white1@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC MOT question
Message-ID:
<1804872568.73138316.1521347958022.JavaMail.zimbra@xxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Hi Chris,
Do you see an improvement in spark length on your VTTC when using a larger
toroid? I have 2 more turns of tuning available on my primary so I can try a
larger toroid if that would help. Also, in lieu of rewinding my secondary, I
have another small Murata Class 1 doorknob capacitor that I can put in
parallel with my primary circuit capacitor to give me some more tuning range
on the primary coil if needed.
Another possible improvement that I am considering is the addition of a heat
shield between my primary circuit capacitor and the vacuum tube. My
capacitor is a Murata Class 1 doorknob and it heats very little, just
slightly warm to the touch. However, the capacitor is only about 2 inches
away from the tube in the interest of keeping primary circuit connections as
short as possible. The idea of the heat shield is to prevent the capacitor
from being heated by radiation from the tube. That being said, I have run
this VTTC for as long as 20 minutes in interrupter mode and have noticed no
degradation in performance and very little capacitor heating so I am not
sure that the heat shield will improve things. It is very easy to add,
however, so I will probably do it.
Steve
----- Original Message -----
From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Friday, March 16, 2018 3:30:07 PM
Subject: Re: [TCML] VTTC MOT question
Hi Steve,
Yes, I am back to my bigger copper tube toroid again. I have said in the
past recently that I always find myself going larger especially if pulsing.
I tried 4 other smaller sizes working back up to this. I have several more
going bigger, but of course they get too physically big for the size of this
coil, and then I would run into frequency problems again, which I want to
also say if you are considering larger, you may want to figure out if you
are going to have a possible frequency problem of pulling it too low.
This is why I rewound my secondary for a higher starting frequency. I have
alot more "headroom" to try various changes.
Yeah, having the feedback above a fairly tall primary can have some
problems. I have mentioned this also in the past. You got lucky you caught
is soon enough and have taken corrective action, I have seen variations of
what you said you did to prevent this.
Me, I have stopped a while ago of the "traditional" above the primary. I
always put it below now. Me, I feel (and some may disagree with me, which is
ok) that even though in theory, it is only supposed to be affected by the
primary, it seems to be affected by the higher voltage built up on the
secondary on the upper end, which happens when you have a taller primary.
If a short traditional primary, it is ok above.
At the bottom below the primary, you are of course located at the bottom of
the secondary, which is mostly current of course, and also has the benefit
of eliminating high voltage short arcs between the feedback and secondary.
I would also say this is much healthier for the grid wire of the tube to
eliminate this from happening.
I will have more details on this later, but I "was" peaking during the
pulses about 23+ amps at "140" 100% variac input.
I have not yet done any changes yet last night or today yet. Kind of taking
it easy...was tired from work. Going to mess around a bit later I think.
I should be able to give more details and comments and pictures this weekend
sometime.
Chris
Sent from my LG V20
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxxxxxx
https://www.pupman.com/mailman/listinfo/tesla
------------------------------
Message: 7
Date: Sun, 18 Mar 2018 17:23:52 +0000
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC MOT question
Message-ID:
<CAPVCm=NvLiUzye7PT9xGM_oTwcZQTRe6s4r0q45=Y-LH-K=WEg@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Hi Steve,
For me, yes I saw improvement. That's why I kept working up. I do this in
conjunction with adding capacitance to the tank. I put a bigger toroid on
first and run coil and verify that the arcs get spoiled, fatter, and
shorter. You want to see this. Then you need to add inductance and/or
capacitance to the tank to then "straighten, stretch" the arcs out longer.
Amp draw should also go up also. Most of the time, not always, just like
John, I have better results adding capacitance also. Since you only have 2
turns left to add which I think is not enough for a bigger toroid. I would
max out your turns, and then add capacitance changes only. You may need to
get and expand your selection of caps for fine tuning. Me, I have pretty
large and wide selection of mica caps to try. You should be fine on your
type of caps, sounds like you need some more selection to have on hand.
Or you can try by what your saying by what sounds like a too big of a cap
and then back off on inductance turns. Sounds like the easiest for you to
try currently.
Then there are the other things that can be adjusted and tried also of
course.
Me, I am able to do very extended run times also. I have added several fans
over time, all over, to extend this even further. Overall pulsing is so
great :-)
Okay, going to get messing with my coil and see if I can break 30", just 1"
shy ;-)
Hopefully, later today, I will post some pictures and more details of what
is all going on with this coil.
Chris
Sent from my LG V20
------------------------------
Message: 8
Date: Sun, 18 Mar 2018 12:20:14 -0400 (EDT)
From: Steve White <steve.white1@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC MOT question
Message-ID:
<729986443.74011062.1521390014439.JavaMail.zimbra@xxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Hi Chris,
I wonder if the problem with my VTTC is the variac? My variac is the
Superior Electric model 116C. This variac is rated at 10 amps but can be
overloaded if the duty cycle is sufficient to allow cooling. Currently I am
seeing maximum current pulses of about 15 amps at 140 volts at an
interrupter period where I get my longest sparks. I am using this variac
because it is small enough to fit into the chassis of my VTTC to make a
portable unit. I have bigger variacs but one of those would have to located
outside of the main chassis thus decreasing portability. From the
information that I see in the Powerstat data sheets, this variac should be
able to supply several times its rated current if the duty cycle is
sufficiently low so I don't think that this is the problem.
I should note that if I run the VTTC in CW mode, it will draw about 19 amps
at 140 volts. As I increase the on-time of the interrupter, the current draw
will rise to about 19 amps max but I get my longest sparks at lower
interrupter rates where the VTTC draws about 15 amps.
Steve
----- Original Message -----
From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Saturday, March 17, 2018 11:55:58 PM
Subject: Re: [TCML] VTTC MOT question
Hi Steve,
Um, yes I did start to have problems blowing or tripping the circuit
breaker, after 3 times, had to quit and correct this. It was impossible to
fine tune further. Realized I have now run into a poor power factor problem
at the increased power level now. I will give some more details later on
what I did for this to correct this. So currently I have added about 224uF
in PF caps. Amp draw is now at the current state of tuning, going from 10
amps to 16 amps pulsing. Much better now! Can actually do tuning changes now
no problem.
So if we can eventually find out why your coil is not drawing more amps, you
do need more to get the extra spark length, you may run into this also.
I think you said you are currently at about 15 amps, of course no power
factor correction.
I have not done anything Sat on the coil. I worked very early that day. Was
tired after and need to get other things done.
But I can now try some things tomorrow (Sunday). I hope to give some more
details and pictures.
Also want to say, sounds like the better filament transformer change with
meter and small variac is worth the effort and time. Besides no more surge
problem of course, benefit of being able to manually regulate voltage is a
big plus. I have some line voltage drop from the heavy draw of the coil
running, pulls down filament some. Most tube spec sheets want you to hold
unavoidable fluctuations to a minimum. Typically .3-.4 + or - max. Going low
is worse. You will see where to set it on the plus side so it does not fall
to low. Me when under coil running, I like to keep at +.2 for a slight
safety margin for other possible load conditions.
Chris
Sent from my LG V20
On Sat, Mar 17, 2018, 9:44 AM Steve White <steve.white1@xxxxxxxxx> wrote:
> Hi Chris,
>
> Wow! 23 amps at 140 volts. That is 3.2 KW. I am surprised that your 20
> amp circuit breaker doesn't blow. I guess the slow-blow action of the
> breaker prevents this especially since you are pulsing.
>
> I think my next step will be to replace my home-made filament
> transformer (rewound MOT) with a commercial filament transformer,
> which I now have, and a small variac and voltmeter for filament
> voltage adjustment. It won't make my sparks any longer but it will be
> much more efficient. My MOT-based filament transformer draws about 750
> watts! It gets quite warm even with a cooling fan. I measured the
> commercial filament transformer under load and it only draws about 120
watts and stays completely cool.
>
> Steve
>
> ----- Original Message -----
> From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Friday, March 16, 2018 3:30:07 PM
> Subject: Re: [TCML] VTTC MOT question
>
> Hi Steve,
>
> Yes, I am back to my bigger copper tube toroid again. I have said in
> the past recently that I always find myself going larger especially if
pulsing.
> I tried 4 other smaller sizes working back up to this. I have several
> more going bigger, but of course they get too physically big for the
> size of this coil, and then I would run into frequency problems again,
> which I want to also say if you are considering larger, you may want
> to figure out if you are going to have a possible frequency problem of
pulling it too low.
> This is why I rewound my secondary for a higher starting frequency. I
> have alot more "headroom" to try various changes.
>
> Yeah, having the feedback above a fairly tall primary can have some
> problems. I have mentioned this also in the past. You got lucky you
> caught is soon enough and have taken corrective action, I have seen
> variations of what you said you did to prevent this.
>
> Me, I have stopped a while ago of the "traditional" above the primary.
> I always put it below now. Me, I feel (and some may disagree with me,
> which is ok) that even though in theory, it is only supposed to be
> affected by the primary, it seems to be affected by the higher voltage
> built up on the secondary on the upper end, which happens when you have a
taller primary.
> If a short traditional primary, it is ok above.
>
> At the bottom below the primary, you are of course located at the
> bottom of the secondary, which is mostly current of course, and also
> has the benefit of eliminating high voltage short arcs between the
feedback and secondary.
> I would also say this is much healthier for the grid wire of the tube
> to eliminate this from happening.
>
> I will have more details on this later, but I "was" peaking during the
> pulses about 23+ amps at "140" 100% variac input.
>
> I have not yet done any changes yet last night or today yet. Kind of
> taking it easy...was tired from work. Going to mess around a bit later I
think.
>
> I should be able to give more details and comments and pictures this
> weekend sometime.
>
> Chris
>
> Sent from my LG V20
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxxxxxx
> https://www.pupman.com/mailman/listinfo/tesla
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxxxxxx
https://www.pupman.com/mailman/listinfo/tesla
------------------------------
Message: 9
Date: Sun, 18 Mar 2018 18:07:23 +0000
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC tubes
Message-ID:
<CAPVCm=OF_uDFQQ+0k5DQhksf-KQ741MH3L7hZQn9KDDgugy-3g@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
You can also start with these tubes and then you can always change to much
more powerful tubes later. The current coil that I am messing with started
with a single 811(not A) tube, oh I think about 30+ years ago. Have tried
several tubes going bigger over the years on it, off and on, as I gathered
up more components slowly over time.
Or go ahead and get a big fella from the get go. You will have to decide.
I would guess 10"-12" with these also like John says. This would be
non-pulsing.
I also prefer more powerful tubes also now.
Chris
Sent from my LG V20
------------------------------
Message: 10
Date: Sun, 18 Mar 2018 20:20:55 +0000
From: Chris Reeland <chrisreeland@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC MOT question
Message-ID:
<CAPVCm=Mac1O-TF0cDT4b6mSvpp9hb5NZuYm5xLpyrn=Y3b_R2w@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="UTF-8"
Hi Steve,
Yeah, I brought that up recently about the variac. I was using a Staco 10
amper. Their spec sheets also say can be overloaded. But for me it did not
like it at all going by my ear (sounded very bad) and I did not see hardly
any gains, no matter the few tuning changes I tried. Did not want to run
long either for the health of variac. So I decided to quit messing around
and get out the bigger one. It also affected the MOT for me, it was noisier
also. So despite what variac spec sheets say about overload conditions, I
have switched to larger variac that I also mentioned recently. Now a 20 amp
Superior Electric Powerstat. Again with this, much quieter. The MOT also.
Unfortunately, yes it is bigger, taking up more room. But I want to push
this coil further and I saw this for me as one of the major roadblocks.
There was other things of course, but I am getting past them too. Been
making nothing but gains all the way so far. Actually I thought 25" was
going to be max for me with the T-200 tube using a MOT for the transformer.
For those that have not been following everything, this is somewhat similar
to a 810. So, I'm a bit smaller than a 833-A. Of course, I cannot run full
tilt long. But the point of this coil to me is all about getting the most
out of it utilizing the advantages of pulsing.
At the minimum, yes should be 24" for a 833-A. Heck, I was happy when I was
at 18" for my tube which was not that long ago, until I really started
messing with it because of you fellas on here having problems and trying
things myself related to our discussions. Just want to say again, I am also
just using #14 NST wire on the primary. I have bigger tubes that are a bit
more powerful than a 833-A that I could switch to right now, same socket
size, but I want to keep using this tube. No real big advantage using my
bigger tubes using the current MOT for the transformer, except being able to
run at higher tilt rates. Actually with a MOT, they would be under utilized
in my opinion.
Best for a future project with a proper big plate transformer. Got some big
fellas. But these MOTs work surprisingly well, I used to doubt them.
Could be a problem in conjunction with your current MOT also. If I am
correct, I think you are still using the NON-Advance MOT. I can't say for
sure on this.
My longest arcs are always at lower rates also, seems to like some "speed"
but not too much also.
I understand your portability problem.
My coil is now anything but. Takes up the whole workbench top now with
everything and meters to monitor things currently. But I am able to make big
changes no problem.
You are going to have to make a choice I guess. Try the cap first and back
off on inductance if needed since you are tight on space of your setup.
Easy to try.
Try lowering grid resistance more also, like we talked about earlier also.
I will give details more later on my current resistance, still
experimenting, not set yet for sure. You may cringe, when I tell you :-)
A lot of rambling here, hope it makes sense.
Okay, back to the new goal of 30" :-)
Chris
Sent from my LG V20
On Sun, Mar 18, 2018, 12:35 PM Steve White <steve.white1@xxxxxxxxx> wrote:
> Hi Chris,
>
> I wonder if the problem with my VTTC is the variac? My variac is the
> Superior Electric model 116C. This variac is rated at 10 amps but can
> be overloaded if the duty cycle is sufficient to allow cooling.
> Currently I am seeing maximum current pulses of about 15 amps at 140
> volts at an interrupter period where I get my longest sparks. I am
> using this variac because it is small enough to fit into the chassis
> of my VTTC to make a portable unit. I have bigger variacs but one of
> those would have to located outside of the main chassis thus
> decreasing portability. From the information that I see in the
> Powerstat data sheets, this variac should be able to supply several
> times its rated current if the duty cycle is sufficiently low so I don't
think that this is the problem.
>
> I should note that if I run the VTTC in CW mode, it will draw about 19
> amps at 140 volts. As I increase the on-time of the interrupter, the
> current draw will rise to about 19 amps max but I get my longest
> sparks at lower interrupter rates where the VTTC draws about 15 amps.
>
> Steve
> <https://www.pupman.com/mailman/listinfo/tesla>
>
------------------------------
Message: 11
Date: Sun, 18 Mar 2018 16:12:36 -0400 (EDT)
From: dave pierson <dave_p@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Subject: Re: [TCML] VTTC MOT question
Message-ID: <1711963189.334111.1521403956906@xxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=UTF-8
> On March 18, 2018 at 12:20 PM Steve White <steve.white1@xxxxxxxxx> wrote:
> I wonder if the problem with my VTTC is the variac? My variac is the
Superior Electric model 116C. >This variac is rated at 10 amps but can be
overloaded if the duty cycle is sufficient to allow >cooling. Currently I am
seeing maximum current pulses of about 15 amps at 140 volts at an
i>nterrupter period where I get my longest sparks. I am using this variac
because it is small enough >to fit into the chassis of my VTTC to make a
portable unit. I have bigger variacs but one of those >ould have to located
outside of the main chassis thus decreasing portability. From the
information >that I see in the Powerstat data sheets, this variac should be
able to supply several times its >rated current if the duty cycle is
sufficiently low so I don't think that this is the problem.
I leave to others more knowledgeable to comment on the symptom match.
choosing
a component for mechanical fit, rather than ratigs can be iffy. jf done,
one
might be sure of cooling holes, a fan, room permitting/
best
dwp
------------------------------
Message: 12
Date: Sun, 18 Mar 2018 16:09:50 -0400
From: Futuret <futuret@xxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: [TCML] VTTC MOT question
Message-ID: <1623abb7c25-1dc1-e8e1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=utf-8
Steve,
I usually use a 10 amp variac same brand and model as you are using, so I
don't think it's the problem. But I suppose a bigger variac might
give some small advantage. I didn't do a comparison.
John
-----Original Message-----
From: Steve White <steve.white1@xxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sun, Mar 18, 2018 1:35 pm
Subject: Re: [TCML] VTTC MOT question
Hi Chris,
I wonder if the problem with my VTTC is the variac? My variac is the
Superior Electric model 116C. This variac is rated at 10 amps but can be
overloaded if the duty cycle is sufficient to allow cooling. Currently I am
seeing maximum current pulses of about 15 amps at 140 volts at an
interrupter period where I get my longest sparks. I am using this variac
because it is small enough to fit into the chassis of my VTTC to make a
portable unit. I have bigger variacs but one of those would have to located
outside of the main chassis thus decreasing portability. From the
information that I see in the Powerstat data sheets, this variac should be
able to supply several times its rated current if the duty cycle is
sufficiently low so I don't think that this is the problem.
I should note that if I run the VTTC in CW mode, it will draw about 19 amps
at 140 volts. As I increase the on-time of the interrupter, the current draw
will rise to about 19 amps max but I get my longest sparks at lower
interrupter rates where the VTTC draws about 15 amps.
Steve
----- Original Message -----
From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Saturday, March 17, 2018 11:55:58 PM
Subject: Re: [TCML] VTTC MOT question
Hi Steve,
Um, yes I did start to have problems blowing or tripping the circuit
breaker, after 3 times, had to quit and correct this. It was impossible to
fine tune further. Realized I have now run into a poor power factor problem
at the increased power level now. I will give some more details later on
what I did for this to correct this. So currently I have added about 224uF
in PF caps. Amp draw is now at the current state of tuning, going from 10
amps to 16 amps pulsing. Much better now! Can actually do tuning changes now
no problem.
So if we can eventually find out why your coil is not drawing more amps, you
do need more to get the extra spark length, you may run into this also.
I think you said you are currently at about 15 amps, of course no power
factor correction.
I have not done anything Sat on the coil. I worked very early that day. Was
tired after and need to get other things done.
But I can now try some things tomorrow (Sunday). I hope to give some more
details and pictures.
Also want to say, sounds like the better filament transformer change with
meter and small variac is worth the effort and time. Besides no more surge
problem of course, benefit of being able to manually regulate voltage is a
big plus. I have some line voltage drop from the heavy draw of the coil
running, pulls down filament some. Most tube spec sheets want you to hold
unavoidable fluctuations to a minimum. Typically .3-.4 + or - max. Going low
is worse. You will see where to set it on the plus side so it does not fall
to low. Me when under coil running, I like to keep at +.2 for a slight
safety margin for other possible load conditions.
Chris
Sent from my LG V20
On Sat, Mar 17, 2018, 9:44 AM Steve White <steve.white1@xxxxxxxxx> wrote:
> Hi Chris,
>
> Wow! 23 amps at 140 volts. That is 3.2 KW. I am surprised that your 20
> amp circuit breaker doesn't blow. I guess the slow-blow action of the
> breaker prevents this especially since you are pulsing.
>
> I think my next step will be to replace my home-made filament
> transformer (rewound MOT) with a commercial filament transformer,
> which I now have, and a small variac and voltmeter for filament
> voltage adjustment. It won't make my sparks any longer but it will be
> much more efficient. My MOT-based filament transformer draws about 750
> watts! It gets quite warm even with a cooling fan. I measured the
> commercial filament transformer under load and it only draws about 120
watts and stays completely cool.
>
> Steve
>
> ----- Original Message -----
> From: "Chris Reeland" <chrisreeland@xxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Friday, March 16, 2018 3:30:07 PM
> Subject: Re: [TCML] VTTC MOT question
>
> Hi Steve,
>
> Yes, I am back to my bigger copper tube toroid again. I have said in
> the past recently that I always find myself going larger especially if
pulsing.
> I tried 4 other smaller sizes working back up to this. I have several
> more going bigger, but of course they get too physically big for the
> size of this coil, and then I would run into frequency problems again,
> which I want to also say if you are considering larger, you may want
> to figure out if you are going to have a possible frequency problem of
pulling it too low.
> This is why I rewound my secondary for a higher starting frequency. I
> have alot more "headroom" to try various changes.
>
> Yeah, having the feedback above a fairly tall primary can have some
> problems. I have mentioned this also in the past. You got lucky you
> caught is soon enough and have taken corrective action, I have seen
> variations of what you said you did to prevent this.
>
> Me, I have stopped a while ago of the "traditional" above the primary.
> I always put it below now. Me, I feel (and some may disagree with me,
> which is ok) that even though in theory, it is only supposed to be
> affected by the primary, it seems to be affected by the higher voltage
> built up on the secondary on the upper end, which happens when you have a
taller primary.
> If a short traditional primary, it is ok above.
>
> At the bottom below the primary, you are of course located at the
> bottom of the secondary, which is mostly current of course, and also
> has the benefit of eliminating high voltage short arcs between the
feedback and secondary.
> I would also say this is much healthier for the grid wire of the tube
> to eliminate this from happening.
>
> I will have more details on this later, but I "was" peaking during the
> pulses about 23+ amps at "140" 100% variac input.
>
> I have not yet done any changes yet last night or today yet. Kind of
> taking it easy...was tired from work. Going to mess around a bit later I
think.
>
> I should be able to give more details and comments and pictures this
> weekend sometime.
>
> Chris
>
> Sent from my LG V20
> _______________________________________________
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> https://www.pupman.com/mailman/listinfo/tesla
> _______________________________________________
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>
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------------------------------
Message: 13
Date: Sun, 18 Mar 2018 15:46:56 -0400 (EDT)
From: Jay Howson LAST_NAME <jhowson4@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>, Futuret
<futuret@xxxxxxx>
Subject: Re: [TCML] VTTC tubes
Message-ID: <332927312.904874.1521402416216@xxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain; charset=UTF-8
Thanks everyone,
Perhaps I will try my hand at a small VTTC with these tubes after all!
=)
Cheers
Jay
> On March 18, 2018 at 9:44 AM Futuret via Tesla wrote:
>
>
>
> Jay,
>
>
> Using a single 4-125A, I obtained a 10" spark if I remember correctly.
> Using your two 4-65A's you might get the same spark length I suppose.
> Personally I prefer more powerful tubes for a VTTC.
>
>
> John
>
>
>
> -----Original Message-----
> From: jhowson4
> To: TCML tesla Coil Mailing List
> Sent: Sat, Mar 17, 2018 10:31 pm
> Subject: [TCML] VTTC tubes
>
> Hello all,With all the VTTC talk recwntly, I have been thinking. I
have a pair of nos amperex 8165/4-65A tetrodes.
http://www.relltubes.com/products/Electron-Tubes-Vacuum-Devices/Tetrode/4-65
A-8165AM.htmlWhat are everyone's opinions regarding usage in a VTTC?-JaySent
from my Verizon 4G LTE Smartphone
> _______________________________________________
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> Tesla@tedward.pupman mailto:Tesla@tedward.pupman .com
> https://www.pupman.com/mailman/listinfo/tesla
>
------------------------------
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