RE: 48KWATT DRSSTC Warmup

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Hooper, Christopher AZ" <christopher.az.hooper@xxxxxxxxx>

Good day,

It will be interesting to see how far I can push 
MMC's. On my 2kwatt DRSSTC @ 
http://users.cableaz.com/~chooper/igbt_fullbrige.htm 
I was running the coil so hard, the coil just 
stop working! Ohhhhhhhhh great, I blew an IGBT; 
however, what failed was the MMC. I melted the 
solder on the MMC bus, hmmmmmmm, what temperature 
to melt solder, now that is a hot! So redesigning 
the MMC; what I found worked is using silver 
solder on all connections, multi bus in and out 
of MMC allowing me to even push the coil harder 
to obtain 80 inch sparks. I wanted to take small 
steps on building larger DRSSTC's, so thought I 
had better make a 10kwatt before jumping on the 
48kwatt. I am sure I will find weak links in the 
10kwatter as will push the coil hard, repair the 
failures, redesign and then take all information 
learned and start the 48kwatter. I really think 
MMC's have great potential for large coils as 
DRSSTC's ring up so fast and dump a great deal of 
RF Amp's into the primary (watching with a CT on 
the primary). Steve Ward has a great picture of a 
CT on the primary @ 
http://www.stevehv.4hv.org/DRSSTC1/scopepics/strike.JPG 
. I will have to design 500 cap MMC with great 
consideration for the current dump into the 
primary by using large copper bus, keeping caps 
close (not to close for flash over) , using 10meg 
ohm ½ watt bleeder/balancer resistors on each 
cap, and running mucho air over caps. I work with 
liquid nitrogen testing chips down to -60c, sure 
wish I could drop the MMC and IGBT's into liquid 
nitrogen, he he (maybe on next coil)!

Willing to take big risk construction larger 
DRSSTC's, failures will happen (whats that smoke) 
but as long as I learn from my mistakes, I guess 
it will not be a loss after all.

Sincerely,
Christopher robin

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Wednesday, January 25, 2006 9:02 PM
To: tesla@xxxxxxxxxx
Subject: Re: 48KWATT DRSSTC Warmup

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

You know, I've wondered if a huge MMC would do well. I don't worry so
much for the caps themselves, but for the lead and connection bus.
I'm not sure what that limit is before degradation, but there is
certainly a limit.

It will be good test in any event.

Take care,
Bart

Tesla list wrote:

>Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
>
>Hi,
>
>MMC are not really "power level limited".  If you stay within the DC
>voltage (or just 100% over :o)) they will be fine ;-))  RMS current
>is a big factor.  Going to 140% of the ratings is usually the limit,
>but newer caps seem to handle RMS current better.  Just don't push
>peak current much!!
>
>If one considers a 10 x 12 array of 14kV RMS and 12 x 13.5 amps RMS
>you get a "sustained and rated" 2,268,000 watts!!!!  So from that
>point of view, 10kW is nuttin ;-))  An overrated "peak" power level
>comes out to say 30000V at  7300 amps for about 1/5th of a giga watt :)))
>
>If they get warm, a fan will increase the air dissipation 500%.  But
>it depends on the internal temperature.  Poly caps can take a
>sustained temperature of 80C for a very long time.  However, that is
>if internal heating is small.  If the internal temp gets to about
>100C, they will blow up...
>
>But really, I would worry far more about the IGBTs than the caps ;-))
>Judging from the looks of the coil, it will work perfect!!!
>
>Cheers,
>
>         Terry
>
>At 06:56 PM 1/25/2006, you wrote:
>
>>The MMC won't take this kind of power level.  You will need to run
>>the big Maxwells like we do on our coils over 6 kVA.
>>
>>
>>Dr. Resonance
>>
>>
>>>
>>>I thought I would share my newest creation, a 10kwatt DRSSTC @
>>>http://users.cableaz.com/~chooper/images/fatboy1wred.jpg .
>>>
>>>Since I use plexy, I thought embedding high output UV LED's would be
>>>cool and looks like a spark gap running from the distance @
>>>http://users.cableaz.com/~chooper/images/fatboyblue.jpg .
>>>
>>>Little red DRSSTC (ran at the Cheesehead)is in front of new DRSSTC for
>>>comparison, as the 10kwatter is almost 8 feet. 120 caps for the MMC and
>>>is fan cooled as I push my MMC's to melt down....he he. First light is
>>>this weekend.....then off to the 48kwatter DRSSTC...... first step of
>>>the 48kwatter is the 9 foot by 3 foot secondary. 48kwatter DRSSTC will
>>>also use a big, very big MMC; start soldering iron up indeed (maybe 500
>>>caps or so)
>>>
>>>
>>>Rgs,
>>>Christopher robin
>>>
>
>
>
>
>