Re: moderate sized TC

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

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.


----- 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
>
>
>
>