Ballast and wire stuff

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Original poster: Mddeming-at-aol-dot-com 

Hi All,

     Well, I'm finally getting ready to retire my NST farm, the OBIT farm, 
the MOT clusters, and plate-supply transformer, and start using my pole pig 
for something more than a doorstop/conversation piece. This brings up some 
questions:

1) I know there is a rule-of-thumb that a couple of 500' spools of #10 wire 
can be hooked onto the primary side as ballast and "all will be well". 
However, I was wondering, " Is there a way to calculate the inductance 
needed to limit the current draw to say, 30 Amps, even in the case of a 
dead short on the secondary?"

2) What transformer parameters are needed to do the calcs beyond the 5 KVA, 
-at-60 Hz. primary 240 V, secondary 14400 V?
3) The off-the-shelf wire spools each measure 0.5 Ohm resistance and ~7.4 
mH inductance.
and #10 wire is nominally NEC rated -at- 30 Amps. In a multi-layered ballast 
coil, inside a cabinet, would these be subject to overheating? Will I need 
a Hollywood-style wind machine and thermal relays in my control cabinet to 
keep from smoking the system?

4) I vaguely remember a posting to this list from Fr. McGahee ca. 1998 that 
said #10 bare copper wire could only handle ~24 Amps Max and about 21 Amps 
steady load, and that was with plenty of free air space. Anybody remember 
why the discrepancy?

Thanks,
Matt D.