Re: Solid State

On Wed, 15 May 1996, Tesla List wrote:
> I took up Harri's suggestion and 
> tried making up some Litz wire - it wasn't very regular but I could
> make it work. 

It won't be too regular with the method I described. Just for the recored:
it is not litz it is a bunch of wires. Still, it beats most of the undesired
effects in wires.

> I got a slight shock of the core when I checked it for heat so 
> something's leaking corona. 

Another possibility is that the core is getting energized by capasitive
coupling to the winding. (Remember, you do have high frequency!) I'd
suggest earthing the core for safety or not toughing it while having
the power applied. Remember that you may get a few kV at quite a high
power if you get a shock from the secundary winding!!

> I asked about potential hazards - Jim suggested pacemakers.
> There could easily be one in our 200+ congregation, but they will
> be some distance 15' min from the 500W solid state coil - is this
> a serious risk?

You'll know when you try it out :)

> Because I'm driving 3 irf740's on each side I buffer the
> outputs with a couple of TC4422cpa  (Farnell or RS)

Make sure you have enough dead time if using several driver chips. If not
you may find the differences making cross-conduction etc.

> I hope this month to finish this design. And then
> start on a half bridge using rectified mains :)

Yes, go for it! It will mean more popped FETs but you'll get more power
and a better spark. :) :)
We have phone numbers already, why would we need IP-numbers! -unknown person

Harri.Suomalainen-at-hut.fi - PGP key available by fingering haba-at-alpha.hut.fi