IGBT long life at 3X rated Ip?? Re: 15kva 14.4 kV Transformer.. (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Moderated and approved by: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sat, 23 Dec 2006 16:17:45 -0700
From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: IGBT long life at 3X rated Ip??  Re: 15kva 14.4 kV  Transformer.. (fwd)

Hi Bart,

It would also have to monitor fire alarms and dump a few thousand cubic 
feet of Halon ;-))  I miss the "good ol days" of having all the ceiling 
tiles blow out and hitting me on the head %:-)))  The vocal alarm giving 
you 30 seconds to abort, or fire "now"...

I use basic stamps and all that all the time ;-))  Your controller sounds 
neat and I would be interested in knowing what kind it is.  Perhaps it is a 
custom thing you use in your work.  Prolly like this:

http://www.parallax.com/detail.asp?product_id=30064

These are cool and I have them but have never had time to really play with 
them...

http://www.rabbitsemiconductor.com/products/rcm3600/

They got powerful ones now too ;-)))

http://www.rabbitsemiconductor.com/products/RCM4100/index.shtml

But the programming of Basic Stamps is at "my" level 0;-))

But I really don't have a fire proof area where a fire or major electrical 
mess could be handled automatically.  Nor could I stand the noise of the 
arcs...  Takes like a block house in the desert or something...  But just a 
controlled primary circuit is all that is needed since the IGBTs "don't 
care" about the top arcs.

The only real concern is how IGBTs stand up to long term continuous massive 
over currents.  If anyone gets say 1000 hours on an IGBT with very well 
known over stresses, we could probably send it to IR for analysis.  I used 
to do that myself but I no longer have direct access to the "stuff".  I 
have friends though who still do it.  Maybe IR or Motorola has already done 
this.  Probably not though...  If we had the parts, they would "love" to 
know as much as we and it is simple to do.

The issue really is what happens to the wire bonds and top metal layers on 
the die.  Current pulses at that level can do really wild things and I am 
not sure if they are "bad" in our time frame.  My DRSSTC IGBTs have copper 
layers on the die which is an odd twist and the SISG die might use copper 
too....

DC's 24 hour test tells a lot, but not at the say 100 day range.  I am 
slightly worried that some problem might be lurking out there "sooner than 
we like" that might kill are poor IGBTs in very long term applications.  I 
was thinking Finn was safe using CM600 bricks, till he started running 4500 
amps!!! :o))))

So somebody has to do something someday to figure out something about 
anything...

Cheers,

         Terry


At 09:31 PM 12/22/2006, you wrote:
>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
>Subject: Re: 15kva 14.4 kV Transformer.. (fwd)
>
>Hi Terry,
>
>No, it's pretty easy. A PLC might be a perfect choice for a long running
>test bed. I use a PLC for my deadman switch, VFD status for the
>sparkgap, etc.. The PLC will react to inputs you state in the logic
>program. The programming is super simple and you can control disconnects
>or whatever in the event of any situation. Software is free.
>
>If your interested in a small 3" x 2" computer (PLC), just contact me
>off list. No charge. It's good for at least 5 years of running. It runs
>on 24 VDC and even has PWM output capability on 2 outputs (including PID
>control). The software is free and like I said, super simple to program.
>
>PLC's can do almost anything. Much depends on the programmer, the task,
>and the number of I/O's. The PLC I have for you if wanted is perfect for
>a test bed controller. You can program a contactor disengagement for any
>situation you deem as "time to shut down". It has 24 inputs and 16
>outputs (more than enough for most projects). Just let me know if your
>interested.
>
>Take care,
>Bart
>
>Tesla list wrote:
..........