RE: OLTC - Inside the PWRX CM600HA-24H

["Tesla list" <tesla-at-pupman-dot-com>]

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.

Cheers,

         Terry


At 04:31 PM 4/15/2004, you wrote:
>Terry,
>
>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?
>
>Adam
>
>-----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
>C.
>uses on his wonderful OLTC.  Mine were a little more "used" since a few
>had
>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
>applied
>a "spread spectrum force instrument" to the case (hammer).  I then
>chopped
>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...
>So,
>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:
>
>http://hot-streamer-dot-com/temp/CM600HA-24H.jpg
>
>Just eight big ~ 20mm IGBT die in parallel and the eight reverse diodes
>on
>a aluminum nitride substrate.  The gates on two have been over voltage
>and
>fried two chips.  Probably another device incinerated and the buss
>voltage
>got onto the gate buss.
>
>Sort of neat.  Be sure not the flex the copper bottom too much ;-))
>
>Cheers,
>
>         Terry