RE: Sparks from an IGBT brick!

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

Original poster: "Steve Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve.conner-at-optosci-dot-com>

 >Before making a new secondary, I think you should put as much power into
 >that secondary as you think it can take! If you increase the break rate to
 >1200 like you did on the little driver, and up the primary energy a little,
 >I think it could be really impressive ;-)).

I'm really not ready to go for the serious power yet :| I don't have proper
instrumentation for primary voltage/current and the control circuit is
unshielded. If it misfired at high power the brick could be destroyed. Plus
my bench power supply only delivers 60 Watts anyway :(

I need to build an off-line power supply that delivers like 600V DC at
several Amps. This won't be too difficult, just a variac, big isolating
transformer, and full-wave doubler, but as you can imagine there are safety
issues involved and I just don't feel happy with firing kW into a rig that
has wires twisted together and things balanced on coffee mugs. It could well
end up being a bit too "impressive"...

Anyway I think it's time to quit talking and start building! I'm going to go
off-list for a while and will return when I have either made some serious
sparks or destroyed both the bricks trying 8->

P.S. Jimmy I suspect your gate drive transformer was just not kicking out
enough voltage to fully enhance the IGBTs... I don't think bricks can be
driven fast enough for Tesla duty with a transformer at all. In fact I had
trouble even with no transformer, the inductance of 7" of wires twisted
together was messing things up. I'll be using 12 Amp discrete gate drivers
each with its own power supply and opto-isolated input, mounted directly on
the bricks :)

And I will just be bussing my bricks in parallel after I read an IR app note
that said the tempco of IGBTs is always positive at high currents :)