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



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



---------- Forwarded message ----------
Date: Sat, 23 Dec 2006 21:38:51 -0800
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: IGBT long life at 3X rated Ip??  Re: 15kva 14.4 kV  Transformer..
    (fwd)

Hi Terry,

PLC's can do whatever you want. Their basically a stamp controller with 
much of the same features. Their used for automation control. I use 
Twido controllers (IDEC designed and built this line but I buy from 
SquareD wo puts their name on it and also Telemecanique, although this 
particular series isn't their design).
http://www.us.telemecanique.com/products/Automation/Programmable_Controllers/Twido/index.html

Documentation is on the left side of the page. The above page shows two 
basic types. The difference is ribbon cable (transistor inputs and 
outputs) and the other is a screw terminal connection. The screw 
terminal style also has relay outputs if wanted. I've got both types. 
Just simple ladder logic and presto.

Take care,
Bart

Tesla list wrote:

>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:
>>    
>>
>.......... 
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