Re: Charging inductors for resonant charging

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Jim,

On 29 Jan 2004, at 17:52, Tesla list wrote:

 > Original poster: Jim Lux <jimlux-at-earthlink-dot-net>
 >
 > At 08:01 AM 1/29/2004 -0700, you wrote:
 > >Original poster: Ed Phillips <evp-at-pacbell-dot-net>
 > >Tesla list wrote:
 > > >
 > > > Original poster: Jim Lux <jimlux-at-earthlink-dot-net>
 > > >
 > > > What sort of sources are there for a 5-15 Henry charging inductor
 > > > for a resonant charging circuit? RMS current would be in the 1-2
 > > > Amp range.
 > > >
 > > > Is this a "wind it on a MOT core" kind of thing?
 > >
 > >         I'm no a magnetics designer but that sounds like a HUGE
 > >         device to me!
 > >If the charging frequency was 120 Hz the reactance of the 5 henry
 > >choke would be about 3770 ohms and the voltage across it at 1 amp
 > >would then be 3770 volts.  If it is to pass 1 amp the wire size would
 > >probably have to be around #22 even for intermittent operation, and
 > >the resulting wire area would require a large core.  Real designers
 > >step forward?
 >
 >
 > So then, what ARE people using for charging chokes in resonant
 > charging systems..

Anybody running a Tesla coil from a ballasted transformer is running
a resonant charging system, a lot without realizing it I daresay.
Whether the system is resonant at mains frequency depends on the
component values of course but unless the system is heavily damped,
there would undoubtably some degree of resonant charging present.
In the case of a welder on the primary side of the transformer, its
mH-range inductance is transformed up to the Henries range on the
secondary side. Not quite the same thing as putting a discrete Henry-
range inductor on the secondary side since where the inductor is on
the primary side, the transformer has to withstand an extra voltage
burden across both its primary and secondary windings for any degree
of resonant charging.

Malcolm