Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
Hi DC,
They are trying to get high coupling with DRSSTCs to reduce the
number of cycles and thus time it takes to bring the secondary
voltage up. This helps to decrease the load on the IGBTs and gets a
better LERT.
LERT is Load Energy Rise Time. The DRSSTC folks have found that
there is an optimal time to energized the secondary to get the best
sparks. This time is fairly fast and demands a higher coupling.
ScanTesla (the computer program) says that coupling otherwise does
not matter too much and couplings like 0.13 might be just fine. But
that is before this fast rise time effect is taken into
account. ScanTesla can calculate LERT, but it does not really judge
what is good or bad. LERT is a little to unknown right now to make
"equations" but it seems to be a real important thing.
LERT might also be why coils with low surge impedance seem to do
well. We really don't know right now what it all means...
Cheers,
Terry