RE: Ok, what is an LTR cap.

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Terry,

On 25 Aug 00, at 22:23, Tesla list wrote:

> Original poster: Terry Fritz <twftesla-at-uswest-dot-net>
> 
> Hi Deano,
> 
> 	The real key here is that in an NST the primary to secondary coupling is a
> little loose so the secondary is sort of free to ring up.
> 
> 	In a pig, with very tight coupling, this degree of freedom would have to
> be the ballast.  So if you rang the secondary up into ultra high voltages,
> the primary would follow via the turns ratio.
> 
> 	It all sounds sort of nasty.  Personally "i" would try in on a computer
> first ;-))  
> 
> 	Off hand, I would think you would divide the ballast inductance by the
> turns ratio squared to get the transformed impedance value of the ballast
> as it looks on the secondary side.  Then choose your capacitor to resonate
> at 60Hz with that value.
> 
> At 220VAC and 10kW at 60 Hz, we could choose a ballast of Xl = 4.84 ohms or
> 12.84mH.  With a 14400 pig that transforms to 3uH.  To resonate at 60 Hz
> the cap value is 2.34F.  An impossibly high cap value...
> 
> So it would appear that there is no chance of getting resonant or LTR
> charging from a pig.  However, if I should have multiplied the square of
> the turns ratio instead of dividing, I would get 127.5nF...  If I have made
> that error (which the book on my lap says I didn't...) then the resonate
> case would be easy...  Perhaps others could please double check my
> reasoning and math here...

The primary ballast inductance should be transformed to the 
secondary side by (Ns/Np)^2 as per your second example. You 
would sure get a good bang when the gap fired if there was no 
primary ballast :)

Cheers,
Malcolm

 
> I would think such a resonant system would make one darn good bang!!
> 
> Cheers,
> 
> 	Terry
> 
> 
> 
> At 10:22 PM 8/25/00 -0500, you wrote:
> >Hi Everyone,
> >
> >I have been following this thread with some interest.
> >
> >snip
> >> >  > > however (and OBIT's), can use LTR's. Could you imagine the
> >> joules for a
> >> > pig
> >> >  >
> >> >  > > using an LTR? I see smoke, fire, wooosh!!! Well, for most
> >> of us, not
> >> > Greg,
> >> >  > > Bill, Hull, etc... or you Chris (yet?).
> >> >  >
> >> >  > Actually, Terry's MMC Calc gives me .351uF.
> >> >
> >> >  For a 240/14.4kv, 694mA, 20,749 ohm pig? Terry is .351uF
msnip...