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

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

Original poster: FutureT-at-aol-dot-com 

In a message dated 7/21/04 7:55:55 PM Eastern Daylight Time, 
tesla-at-pupman-dot-com writes:

>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).


Kreso,

I looked at the coil and it is nicely built.  That looks like a nice
tube too.  Let's see 20cm is about 8".  You still didn't give the
specs for the tube i don't think, and that is the most important
thing in trying to calculate the spark length that the coil may
be capable of .   Do you have the specs for the tube?
Also is the tube new or used?  If used it's possible
the tube has low emission, but in that case you'll usually see
a brownish uneven coating on teh inside of the tube glass.
Sometimes the coating will be there, but the tube will still
give full rated power.


>I do not know what should get red in this tube.


In the middle of the inside of the tube is the cylindrical plate.
It's the main thing you see inside the tube.
This plate can get red at very high power.  If the plate is
graphite, then it's not supposed to run red.  If the plate
is sheet metal then it is OK to be red.  The redness is
from heating from bombardment by electrons.  If the plate
gets red, it can mean the various things.  If the plate
doesn't get red it can mean various things too.  Preferably
it means the tube is processing a lot of power.  It's not
so much that the plate "should" be red, simply that redness
can be a sign of high power operation.  In a normal tube coil,
one can always turn down the power some for a shorter spark
and the redness will go away.  Whether the tube is red or
not can give clues to the coil's operation to an experienced
tube coiler.


>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?


The photo was difficult to see clearly.  To me it appeared that the
primary was twice the diameter of the secondary.  But this does not
agree with what you say above so I don't understand.  Can you
clarify this issue?  In any case the primary should be twice the
diameter of the secondary for a cylinder type primary, for a coil of
that size.  Was the feedback coil the same diameter as the primary?
Was the feedback coil below or above the primary?
Or was the feedback coil wound outside of the primary?


>Higher coupling, maybe better sparks?


well high coupling is good up to a point, but probably not too
critical.


>Looks like my tank casp is to smal but we will se.


indeed we will.  A too small cap will require the use of a large
inductance.  Such a situation will tend to create a high tank
impedance.  This will limit the power through the system and
keep the spark lengths short unless a higher voltage is used.
Of course a higher voltage may destroy the tube.


>Well anyway would it help to use samller primary?


see my comments above.

John

>Best Regards
>
>Kreso Bukvic