Re: It works! Solid state driver

From: 	RODERICK MAXWELL[SMTP:tank-at-mail.magnolia-dot-net]
Reply To: 	tank-at-mail.magnolia-dot-net
Sent: 	Wednesday, December 10, 1997 8:35 PM
To: 	Tesla List
Subject: 	Re: It works! Solid state driver

Tesla List wrote:
> From:   bmack[SMTP:bmack-at-frontiernet-dot-net]
> Sent:   Tuesday, December 09, 1997 7:44 PM
> To:     Tesla List
> Subject:        Re: It works! Solid state driver
> Max,
> Your Pwm had an adjustable "dead time" delay which is supposed
> to avoid simultaneous conduction of the power transistors.
> Did you set this for the rise/fall spec's of your FET's?
> This may be the problem.
> Jim McVey

   Yes the dead time is set per instructions. My problem seems to be
"Flux Walking". When I monitor the current on the o'scope using a
current transformer one half of the waveform clearly has much higher
peaks. This indicates one transistor is pulling the majority of the
current. Dead time is also plainly visable as a flat section in the
waveform when neither transistor is conducting. My new power supply will
be a split supply with the center-point of the series capacitors earth
grounded. This will enable me to monitor the drain voltage/waveform
directly. Before I put the push-pull driver back together I think I'll
try my hand at a flyback. It will probably be a little easier. I have a
HUGE npn bipolar transistor sitting on the shelf, gathering dust I've
been meaning to use. It's made by Westinghouse, and is rated at

                                Frankensteins Helper