Re: All who know VTTC stuff ;-). (fwd)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Kreso Bukvic" <kreso.bukvic-at-kc.htnet.hr> 

Well i tried smaller primary but evrything was sourounded by corona.

Im winding the big one today.

But i still do not know should first turn of primary be equal with first
turn of secondary, or?

Best Regards

Kreso Bukvic
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, July 22, 2004 1:48 AM
Subject: Re: All who know VTTC stuff ;-). (fwd)


 > Original poster: Kreso Bukvic <kreso.bukvic-at-kc.htnet.hr>
 >
 > Ok here you can see the old look and how im rebulding the coil.
 >
 >
http://free-kc.htnet.hr/Kreso-Bukvic/Teslin%20transformator%20s%20vakumskom%
 > 20cijevi.htm
 >
 >   It maked 20 cm sparks not 20 inch ( i wish it would).
 >
 > I do not know what should get red in this tube.
 >
 > Well anyway im thinking my secondary has a diameter of 7 cm and my last
 > primary had a diameter of 17 cm. Im thinking to resize my primary to 11
cm?
 >
 > Higher coupling, maybe better sparks?
 >
 > Looks like my tank casp is to smal but we will se.
 >
 > Well anyway would it help to use samller primary?
 > Best Regards
 >
 > Kreso Bukvic
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Tuesday, July 20, 2004 2:38 AM
 > Subject: Re: All who know VTTC stuff ;-). (fwd)
 >
 >
 >  > Original poster: FutureT-at-aol-dot-com
 >  >
 >  > In a message dated 7/19/04 6:43:19 PM Eastern Daylight Time,
 >  > tesla-at-pupman-dot-com writes:
 >  >
 >  > >Im really sory. The shematics will be on my server soon, but here are
the
 >  > >"specs", i remowed the feedback winding because i will rebuild this
coil
 > i
 >  > >think it was a crap.
 >  > >
 >  > >Secondary
 >  > >Diameter: 70 mm
 >  > >Winding: 1000 turns of 0.4 mm wire
 >  >
 >  >
 >  > This is approximately 26awg wire.  such wire works well at least up
 >  > to a 40" spark.  I used 28 wire (which is thinner) for my 40"spark
VTTC.
 >  > 70mm is almost 3" so that's OK too.
 >  >
 >  >
 >  > >Primary
 >  > >22 turns of 1 mm wire
 >  >
 >  >
 >  > Sounds like you're using about 2kV with level shifting for
 >  > 4KVAC or so?  That's good, but the primary wire is kind of
 >  > thin if your sparks are 20" long or so.  I forget how long they are.
 >  > It would be good to have wire that is at least 2mm thick.
 >  >
 >  >
 >  > >Feedback
 >  > >24 turns of 0.63 mm wire
 >  >
 >  >
 >  > This is OK.  The feedback coil does not handle much power.
 >  >
 >  >
 >  > >Tube - QB 3.5 - 750 tetrode
 >  > >Tube used as triode ( screen and grid connected together)
 >  >
 >  >
 >  > I'm not familiar with the specs of this tube.  But if it has a graphite
 >  > plate then it is probably robust.  It would be helpful to know the
 >  > specs of this tube.  Of course some tubes can be run with more
 >  > power than the specs would suggest.
 >  >
 >  >
 >  > >Filament transformer 5 V 30 A ( it has writing " Property of coherent
 >  > >radiation laboratories California - anybody ever hear for them?)
 >  >
 >  >
 >  > Never heard of them, but it is fine.
 >  >
 >  >
 >  > >PSU
 >  > >Mot with shunts, 2 uF cap and a diode affocurse
 >  >
 >  >
 >  > Is the MOT similar to USA/Japanese type MOT's?  about 600 to
 >  > 800 watt rated at 2kV or so?
 >  >
 >  > >Power controled by variac and evrything has a relay startup and
imeditate
 >  > >stop button
 >  > >Diode protection capacitor 16 kV 1600 pF
 >  > >
 >  > >Main primary capacitors
 >  > >
 >  > >200 pF 20 kV
 >  > >400 pF 16 kV
 >  > >
 >  > >in parallel for 600 pF
 >  >
 >  >
 >  > that is a little small, but will work.  A larger cap will help
 >  > to pull more power through the coil by lowering the tank impedance.
 >  >
 >  >
 >  > >Topload copper pipe oldered arround copper circle and a insulator on
top
 > (
 >  > >very small toroid)
 >  >
 >  >
 >  > very good.
 >  >
 >  >
 >  > >It has a anode current meter too, at biggest sparks anode current was
 > almost
 >  > >300 mA.
 >  >
 >  >
 >  > Was the tube plate red at this power level?
 >  >
 >  >
 >  > >This is what im seeking now
 >  >
 >  >
 >  > What is the grid resistance and grid capacitance?
 >  >
 >  >
 >  > >Im going to rebuild the coil on a new wodden platform, i guess my
primary
 >  > >and feedback were BS.
 >  > >
 >  > >By reading the Steves site im plaining to use 0.4 mm wire for feedback
 > and 2
 >  > >mm wire for primary? What do you think?
 >  >
 >  >
 >  > Yes, that is good.
 >  >
 >  >
 >  > >Well write as much you can and as much you want :-).
 >  >
 >  >
 >  > How long are the sparks again, I forget?  Did you try tapping
 >  > along the primary to tune the coil?  Or did you tune some other way?
 >  >
 >  > In general as long as you more or less copy someone's design,
 >  > you should tend to get similar results.  To get longest sparks
 >  > will take optimization for staccato.  In other words if the coil
 >  > is made to work wtih the tube not too red without staccato,
 >  > then it will not give much more spark length with staccato.
 >  > But if teh coil is optimized for staccato, then the tube will
 >  > get too red without staccato, but the spark will be longer.
 >  >
 >  > John
 >  >
 >  >
 >  > >Best regards
 >  > >
 >  > >Kreso Bukvic
 >  >
 >  >
 >  >
 >  >
 >  >
 >  >
 >
 >
 >
 >