RE: SSTC Reliability

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

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >what is the likelyhood of being able to produce high powered
 >SSTCs (e.g. 10 KVA or more) with museum quality reliability?

It should be quite possible to produce a DRSSTC that will survive any kind
of abuse. I have figured out the required protection circuits, and the
design equations for predicting worst-case peak primary currents and tank
capacitor voltages.

However, it would take an awful lot of work to get everything debugged, sort
out all the EMI snags, and get it working in practice. I've already been
through all this to produce a reliable design for the OLTC, and it'll be a
while before I can be bothered doing it all over again for the DRSSTC.

For what it's worth, the reliability of my crowbar protected OLTC circuit
seems to be pretty good. I have done quite a few runs and demos with the
OLTC II. When used without a breakout point it tends to strike its own
primary, which invariably triggers the crowbar and shuts the whole system
down. I have had about a dozen such "events" plus various primary-secondary
flashovers caused by poor RF ground, but I haven't lost an IGBT brick yet.

On the other hand, the DRSSTC promises about twice the spark length of an
OLTC for a given input power (and also for a given sum of money spent on
IGBTs and tank capacitors) so it's a goal well worth pursuing.

Dan McCauley and Steve Ward have also done excellent work on improving
DRSSTC reliability but I'm sure they will tell you about it themselves.

Steve C.
http://www.scopeboy-dot-com/tesla/