Re: Recent s.s.t.c. work

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jimmy Hynes <jphynes@xxxxxxxxx>

Hey Ken,

I'd be hesitant to come to that conclusion. IGBT gates can go pretty 
freaking high before they fail (I have tested mine to 50v, and 
remember an application not saying 50% survival was at 70-80v!), and 
the gate shorts out when the CE is overvolted, or the device 
overheats as well. How high were you running the gate voltage?

It can be frustrating when you think you fixed a problem, and it 
happens again. You don't want to lose any more motivation!

Good luck,

Jimmy

On 11/29/05, Tesla list <<mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx> wrote:
Original poster: "K. C. Herrick" <<mailto:kchdlh@xxxxxxx>kchdlh@xxxxxxx>

Just to assure some of you that I've not totally given up yet...

As I've mentioned before, I find that at my advanced age I'm losing
the motivation to continue "making things"--as I have been doing for
~70 years.  So I haven't done anything further yet on trying to find
the source of the problem with my new s.s.t.c.  I think that I have
set the peak gate voltage too high, and consequently shorted the gate
of one of the bricks.  I can readily reduce that by 5V and I have 2
more good bricks; it's just a matter of getting around to it.

Finn Hammer mentioned potential problems with putting the primary
inside the secondary, as I have done.  I think my solution to that
would be to raise up the entire secondary so that the bottom of it
was more or less at the top of the primary winding.  Then, add an
auxiliary secondary, of sufficiently larger diameter, aligned with
the primary and of more or less the same height.  That way, I keep
all the existing hardware and only have to fabricate the relatively
simple auxiliary coil and its former.

So the steps I need to take are clear.  I'll likely get to them some
time after the holdiays are over.

Ken Herrick