Re: Solid State - progress.

To: tesla-at-pupman-dot-com
Subject: Re: Solid State - progress.
From: bigr-at-teleport-dot-com
Date: Thu, 06 Jun 1996 22:11:16 -0700
Cc: Tesla-list-subscribers-at-poodle.pupman-dot-com

I'm not sure from reading the message what type of solid state system 
you are building.

Here I have a multi-MOSFET multi KW peak power pulsed driver that I 
connect to a "resonant coil" (i.e. not really a tesla coil since it is 
not a transformer).  My coil is like a "magnifier" without the Tesla 
coil driver.  Or like a 1/4 wave antenna if you're into radio.  It has 
about a mile of 30 gauge wire on it and resonated somewhere in 
50-75khz range, I forget.  Puts out 150kv plus at higher current I 
believe than ordinary Tesla coils.  Is wound on huge poly bucket.

I got the idea from the driver from an old hobby magazine that used 
bipolar transistors.  Mine has four IRF740's in half bridge and I 
pulse them at the limit of their SOA curve.  I use a UC3825 very high 
speed current-mode PWM IC to control the mosfets, and a LM555 to 
control the duty cycle of the power "on" time.  I sense primary 
current in the ferrite transformer and its neat to see current mode 
come into its own with the coil when it is not tuned to resonance.  
The half bridge output is connected to a huge ferrite core 
(77material) transformer from a 1kw power supply.  I believe that I 
use 10 turns of 12 gauge teflon wire for the primary and about 200 
turns of ?? gauge for the secondary.   

I need to put together a schematic as this project is one of the few 
that I now have without documentation.  but if there is any interest, 
maybe I can get motivated to do this.

best regards, Rob. N3FT.