RE: 48kW DRSSTC

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Conner <steve@xxxxxxxxxxxx>


 I just want
to bring the coiling of DRSSTC to a more run time and less bench time
repairing blow bricks and such.

Well so do I. But my plan of attack is to try and design a system 
that won't blow IGBTs in the first place.

My driver has overcurrent protection and reacts in a sane way to 
missing or bad feedback signals. I also believe in pushing the IGBTs 
somewhat less hard than other DRSSTC builders do. I try to avoid 
going much over the manufacturer's absolute maximum current rating. 
It may mean using almost twice as much silicon for a given spark 
length, but I bet I will end up spending less on silicon in the long 
run, if I never blow any.

The bigger the coil gets, the more important it is to do it right 
first time. By the time you get to the 48kW level, I reckon each 
inverter blow-out will cost you a couple of thousand dollars, if you 
include the cost of the silicon, shrapnel damage to nearby 
components, the time that your hired football field and generator 
truck spend sitting idle while you do repairs, and the damage to your 
flak jacket. :-o

On my current research coil, I used 40N60s and set the primary 
current limit to 400A. (the frequency is around 220kHz.) I have got 
sparks up to 4.3 times the length of my secondary, and too many 
flashovers and primary strikes to count, but never lost any IGBTs 
yet. You can't get less bench time than none.

Steve Conner
http://www.scopeboy.com/