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RE: OLTC - Inside the PWRX CM600HA-24H

Original poster: "Steven Ward" <srward16-at-hotmail-dot-com> 

Ive bought a few lots of bricks from ebay from CTR surplus.  They are great 
people there and ive only 1 time had a bad brick in the bunch (which they 
even replaced for me!).  None of mine ever had a big X on them, not even 
the 1 dead one i got.


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: RE: OLTC - Inside the PWRX CM600HA-24H
>Date: Thu, 15 Apr 2004 17:18:54 -0600
>Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
>Hi Adam,
>The "X" means that whom ever was looking at it was "all worried"...  They 
>are replacing "everything" on a failure and pretty minimal trouble 
>shooting is going on out there.  I would look at the ones with the "X" 
>super close, but they may indeed be just fine....  Simply looking at the 
>gate to source resistance tells a lot about the condition.  It should be 
>+10Meg ohm...
>Then, if the resistance across the switch is just not a dead short, it is 
>probably fine.  It is just a "big" IGBT.  All the leads should still 
>simply measure as expected for the device.
>         Terry
>At 04:31 PM 4/15/2004, you wrote:
>>I got 10 of these bricks from CT something surplus on ebay for like $30
>>They all have X on them. Two tested fine and shipped them out to a
>>seller today.
>>What does this X mean?
>>-----Original Message-----
>>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>>Sent: 15 April 2004 05:11
>>To: tesla-at-pupman-dot-com
>>Subject: OLTC - Inside the PWRX CM600HA-24H
>>Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
>>Hi All,
>>I got a batch of those 600 amp 1200V PowerX CM600HA-24H IGBTs that Steve
>>uses on his wonderful OLTC.  Mine were a little more "used" since a few
>>red tech grease pencil "X"'s one them...  Hey!  I know what that means
>>:D  They did the preventive maintenance of replacing the IGBTs a few
>>milliseconds too late...
>>No problem since I got them at 1% the retail price ;-))
>>It read "gate ****** up" on the meter.  So I pulled the screws and
>>a "spread spectrum force instrument" to the case (hammer).  I then
>>the buss bars and dug through the "gorilla snot" as is typical for those
>>familiar with the high art of de-kitting large brick power devices...
>>as if Hot-streamer was not bogged down tonight with all 1500 of you
>>downloading the cap x-ray pics :o))), here is what is inside:
>>Just eight big ~ 20mm IGBT die in parallel and the eight reverse diodes
>>a aluminum nitride substrate.  The gates on two have been over voltage
>>fried two chips.  Probably another device incinerated and the buss
>>got onto the gate buss.
>>Sort of neat.  Be sure not the flex the copper bottom too much ;-))
>>         Terry