Re: [TCML] 35 KVA Vacuum Tube Tesla Coil

[Futuret <futuret@xxxxxxx>]

My understanding is that transformer saturation occurs due to over-voltage,
not due to over-current.  I assume that Roger is applying his 240 volts to
the 240 volt winding of the pig.  If he's putting 240 volts into the 120 volt
winding, then yes that would cause saturation.  Over-current conditions just 
increase the copper and
lamination steel losses.  In a spark gap TC using a ballast, the ballast can
resonate and raise the transformer voltage and cause saturation, but the
standard VTTC design generally doesn't use a ballast.  

During initial adjustments of my 36" spark VTTC when it drew 100 amps
or more, it dimmed all the lights in the house very noticeably.  I don't remember
if I was running on 120 volts or 240 volts that time.  I should look that up in my notes.  
I got it down to 28 amps or so at 240 volts eventually.  

A big key for VTTC efficiency is to keep the tube conduction angle low
enough (strong short feedback pulses to the tube).  On the other hand
you don't want the tube grid voltage to go higher than the plate voltage
on the positive peaks.  Grid leak bias operation requires that the grid
goes positive at times.  

Cheers,
John

 

 


 

 

-----Original Message-----
From: Phil Tuck <phil@xxxxxxxxxxx>
To: 'Tesla Coil Mailing List' <tesla@xxxxxxxxxx>
Sent: Thu, Jul 7, 2011 12:04 pm
Subject: RE: [TCML] 35 KVA Vacuum Tube Tesla Coil


PF issues aside, I would imagine the transformer core to be totally

saturated and most likely the ballast as well, unless it possess a very

substantial core size. The trouble then is that the sine wave loses it's

shape and the meter, depending on the sort used, will give differing false

results. 

Therefore, your coil is actually more impressive than what you though for

the power Roger!



Regards

Phil Tuck



 
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