Re: 48kW DRSSTC

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jimmy Hynes <jphynes@xxxxxxxxx>

Hey,

2) The streamer current is common mode. It came effectively from a
capacitor whose other plate is RF ground, and it wants to go back to
RF ground. If there is no nice AC path from the primary circuit back
to RF ground, the streamer voltage will go flying through everywhere
untill it "Finds" RF ground. That can couple nasty things through
your GDTs etc. back into the driver.


Yeah, you just have to be careful to make sure there's no 'bad path' 
it can find. My DRSSTC survived a bunch of primary strikes, although 
one strike did kill it. When I opened it up, it turns out that the 
spike found its way to the 120v mains, through a wire that happened 
to be laying across the circuit board. Once that connection was made, 
the circuit board was pretty trashed. I just decided to use my 
backup, and give up on it :P The IGBTs survived.

If it's designed with primary strikes in mind, there's no reason they 
should do any harm. If it isn't, it's a gamble. Making a strike 
'cage' for the primary pretty much eliminates the risk of primary 
strikes. I'd like to say that keeping the wire off the circuit board 
fixed the problem, but I don't think it has ever been hit again with 
my 4 strike rails around it :-)