Re: moderate sized TC

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

HI Jim,

On 5 Sep 2002, at 21:28, Tesla list wrote:

> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
> 
> Indeed, the numbers run ok, but I've just never seen big, high performance
> TCs with so few turns on the primary (OLTC excepted, of course...), so I
> wonder if there is some subtle side effect (field distributions, coupling,
> etc.).  Maybe there is a loss/Q issue here, because with low voltages,
> currents will be high and IR losses will get bigger.

I have a similar coil that can produce 5'+ discharges with about the  
a bit less Ep, breakrate varying between 100 and 200, and four turns 
on the primary. Again, the number of turns really isn't the issue. A 
really good secondary can actually make up some lost ground for a 
really bad primary.

Regards,
malcolm


 
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Thursday, September 05, 2002 6:27 PM
> Subject: Re: moderate sized TC
> 
> 
> > Original poster: "Malcolm Watts by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> >
> > Hi Jim,
> >
> > On 5 Sep 2002, at 17:47, Tesla list wrote:
> >
> > > Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <jimlux-at-earthlink-dot-net>
> > >
> > >
> > > Just fooling around to ballpark things for a multi coil setup.
> > >
> > > Secondary 12" in diameter, 48" winding, #20 wire, spacewound for about
> 750
> > > turns about 37-38 mH, 22 pF Cself
> > > Topload, 8-12" tube, 48 diameter overall - about 52 pF
> > >
> > > Fres(sec) = about 100 kHz
> > >
> > > Primary, flat spiral, copper pipe, 6-8 turns, 48" OD, 20" ID (i.e. 4"
> > > clearance from sec bottom - about 50 uH
> > >
> > > Cpri needs to be about 0.06 uF
> > >
> > > Charged from DC source at 11-15 kV... here's the problem.. I'd like to
> be
> > > able to put around 5kW through the system, and with the fairly small
> cap,
> > > you can only store around 6 Joules/bang, and at 200 bang/sec, that's
> only
> > > 1350 kW.
> > >
> > > Ideas: Use resonant charging, so Vpri can be twice source voltage: say,
> > > 20-25 kV, so Ebang = 12-18 J, => 2400-3750 kW
> > >
> > > Could reduce Lpri, which would increase Cpri, and hence Ebang (for the
> same
> > > voltage)but it strikes me, as a gut feel thing, that going to 5-6 turns
> on
> > > the primary is pushing things.
> > >
> > > Suggestions, comments?
> >
> > I think your proposal would still work quite nicely. What really
> > matters in the primary is the inductance/reactance at Fr, NOT the
> > number of turns. You'd need a fairly robust gap. You might be nicely
> > surprised at how well it will do with 6J at 200BPS. The big topload
> > is a plus and the minor topload diameter would be better closer to
> > 12" rather than 8".
> >
> > Regards,
> > malcolm
> >
> >
> >
> >
> 
> 
> 
>