Re: 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: Sun, 24 Dec 2006 11:14:47 +0100
From: Finn Hammer <f-h@xxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: IGBT long life at 3X rated Ip??  Re: 15kva 14.4 kV  Transformer..
    (fwd)


Terry,

"Us" that commercialized the solid state coil ;-} have been running 
multithousand amps for years.

A replica of Steve`s 2-brick OLTC motor is running in museum service, 
and it is counting 1 1/2 year now.
The coil is intermittent running, In short 116 ringdown long bursts, to 
simulate lightning strikes. These bursts are 0.3sec long at 300BPS. That 
ads up to around 1 hours total a day. So a very rough guess is that it 
is up to around 200 hours now. This coil is using PRX CM600HA-28H`s, 
doing up in the high 3000ths of amps.

If IR would supply me with replacements, I could swap them out on a 
service visit.

But if they fail, I`l post the results, of course.

Cheers, Finn Hammer

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