RE: Bi-Polar DRSSTC

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dr. Spark" <azdrspark@xxxxxxx>

Hi John,
No I have not had an opportunity to scope out what the bit rate is, I just
push the interrupter till the IGBT's can not switch. Next time I run, I
will mark the knob and scope it.
 I am using Siemens IGBT's. They are rated at @200A, 1200VBVce,+-20V Vge.
It is a full bridge @ http://www.drspark.org/images/new%20engine2.jpg and
http://www.drspark.org/images/newengine1.jpg and using solid cooper bus.
What save me are two things I think? One is I am running a great deal of
decoupling @ http://www.drspark.org/images/newcaps11.jpg. (I cooked my old
one.whooooops) I ran the coil once without these caps and blew two IGBT's
right out of their socket (I am running wild primary currents with only a
little more than one turn on the primary). Also I am running pure DC
source, which are four big filter caps @
http://www.drspark.org/images/bpcap3.jpg on the rectifier.  With no
doubler, the power into the bus is very clean. All the decoupling may not
be a good thing on most DRSSTC's, as may cause issues with all those leads
increase inductance and could cause more bad than good, but this design
worked well for me.

You have to see this coil run in person, as video just does not do it
justice, man is it loud!

What I am looking at now is this effect on the output @
http://www.drspark.org/images/closebp3.jpg and
http://www.drspark.org/images/closebp1.jpg

I like the way it sprays sparks off the stingers. That is a lot of energy
trying to get off.

Best Rgs,
Christopher @ www.drspark.com

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, January 02, 2007 10:05 PM
To: tesla@xxxxxxxxxx
Subject: Re: Bi-Polar DRSSTC

Very nice work Chris.
I have a few questions after watching your video.
1) Have you scoped the controller circuit to see
what BPS you are running the DRSSTC at? It does indeed scream!

2) What IGBTs are you using? I couldn't tell if
it was a half bridge or full bridge.

This is of interest to me because when I run my
DRSSTC at that screaming BPS I usually, (and
quite undramatically) blow my IGBT's.
I can run for an hour at lower BPS.  Yes, I do
push the coil and IGBT's and certainly duty cycle
is a factor, but there may be more going on too.

Great video and it was nice to meet you at Cheesehead.
John

John W. Gudenas, Ph.D.
Professor of Computer Science



On Jan 2, 2007, at 9:25 PM, Tesla list wrote:

>Good day,
>
>Thought you would enjoy some pictures of my little BI-Polar DRSSTC @
>
>http://www.drspark.org/bi_polar.htm
>
>Video @  http://www.youtube.com/watch?v=os1FbjORGN0
>
>Slide show @  http://www.youtube.com/watch?v=7xnIntH1XjY
>
>This has to be the loudest coil I have, it screams.!
>
>Not really a power hog as only takes 6 amps at 150 volts, no doubler.
>
>Rgs,
>Christopher @ http://www.drspark.org/
>
>