[TCML] Hot Primary

[Dave Leddon]

As I push my DRSSTC into ever higher currents (presently limited to 
3000 amps) I am experiencing some significant heating in the primary 
circuit.  I can see that in the future, as we push the envelop with 
even higher power silicon, we may have to resort to water 
cooling.  Even with 3/4-inch od type L soft copper water pipe (was 
that ever a bear to bend) the primary becomes too hot to touch after 
running the coil for one minute.  I even changed the 
interconnecting  wires from #4 to #2 welding cable to prevent 
meltdown, but oddly the larger wire gets just as hot.  I wonder if 
there isn't some sort of rf heating effect unrelated to voltage drop 
which is generating some of the heat.  A related issue which has been 
bugging me for some time, why are the active primary turns 
progressively warmer as you move inward toward the secondary?  One 
would think that all turns carry the same current.

Dave Leddon
Pleasanton, CA