# Re: Theory - primary cap duty -transformer output current

```Original poster: "BunnyKiller by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bigfoo39-at-telocity-dot-com>

Tesla list wrote:

> Original poster: "PotLuck by way of Terry Fritz <twftesla-at-qwest-dot-net>"
>
> My inquiry focuses on transformer current and the primary cap.
> My understanding is that once the primary cap is charged and the firing spark
> occurs that the transformer's current during the HV pulse and "ringing"
are no
> longer a factor, that the energy stored in the primary cap becomes the sole
> provider of current in the tank circuit.

Snipperzz...

HiPot     ( snickerz) its a joke HiPot test ....

anyway ...   there are 2 schools of thought on cap charging and
discharging...   some say 4 times
per full cycle some like 2 times per cycle...

the 4 times per cycle is when you take the starting voltage at 0 degrees (
0 V ) and allow the first
90 degrees to charge the cap to a " positive " full volt rating, fire the
gap there ( SRSG works
great here) the full potential of the charged cap gets dumped into the
primary at this time. From 90
degrees to 1880 degrees the "Positive" voltage is on the down fall ( this
is where i get lost) ((
only thing I can think of is that the voltage from "full" to dropping does
allow a bit of charge to
fill the cap as it is falling, but the time it has to do it in is minimal))
at 180 degrees the gap
fires again, thus discharging that bit of charge in the cap. Then we swing
into the " negative" side
of the voltage swing ( V going negative on the sine wave) and this charges
the cap in the reverse
polarity ( this is why DC caps dont work with coiling ) at 270 degrees the
gap fires again at full
"negative" voltage. and the cycle continues .......

the other idea is that the cap gets charged to full positive voltage at 90
degrees and cap is
discharged at that point...  and time is allowed to let the voltage after
the initial firing go back
to 0 volts ( ??? ) at 180 degrees. This then reverses and the negative
voltage begins to increase to
the opposite potential.. and at 270 degrees the gap fires again....

Heres the clincher tho....  just after the gap fires, the primary coil and
cap do the oscilation
thing ( this is what allows the secondary to be matched in frequency (
tuning the primary) This
oscillation action removes alot of the power and voltage from the cap ((
this must happen fast cuz
how else does the cap get recharged ???  my turn for a question ... how
got the answer for me ??  ;)  ))

another question...   when the gap misfires how does this overcharge the
cap and blow it? where does
this extra voltage come from??

sheeshhh  now im thinking again ;)

Scot D

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