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Re: [TCML] spark gap substitute...?



The data sheet show maximum frequency of 2kHz.
I bought 2 supposedly 1400 volt 90 amp SCR's but when I asked for documentation for these claims, none were forth coming. I went ahead and sent them back for a refund, not wanting to try anything at voltages like these if I weren't certain about what they could handle.

The only number I can find for them is AA750CRG120BX25 and they do not have any manufacturer information on them at all. They look nearly identical to the IGCT's in that ad but this number doesn't match anything this company has for anything they make. I looked all over their web site, since it doesn't have a search engine. I have also searched the Internet for hours and found exactly nothing.

Does anyone know anything at all about these SCR's, if that is truly what they are? The guy I bought them from was going by what someone "told" him and he doesn't have a clue.

I would appreciate any help because if they really are rated 1400 volts at 90 amps, I would still like to have them.
Paul
Think Positive

----- Original Message ----- From: "Steve Ward" <steve.ward@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Wednesday, January 27, 2010 5:46 PM
Subject: Re: [TCML] spark gap substitute...?


That article sure is vague about IGCTs.  I suspect they are still rather
di/dt limited when compared to IGBTs.  Maybe they would work at 10khz or
something with a lot of effort put into getting zero current switched
conditions.

Funny how they list no deficiencies for the IGCT.  Its more of a sales ad
than anything that useful about IGCTs.

Looking at a real datasheet, the deficiencies seem obvious to me:

http://www.polovodice.cz/_files/specifikace/ti918l-600-25.pdf

Switching speed is several uS (better than i expected, honestly), but the
typical turn off energy is in the 1J range (quite huge compared to an
IGBT). This means these things wouldnt stand a chance in a DRSSTC where the switches control the primary current directly, but they might possibly work
as a "spark gap replacement".  Though you would still need to mind the
switching speed issue and make sure the primary di/dt doesnt kill the
device.

Until they start showing up on ebay or surplus, i doubt anyone is going to
build a TC with them (though it looks quite feasible).

Steve

On Wed, Jan 27, 2010 at 12:48 PM, Dex Dexter <dexterlabs@xxxxxxxxxxx> wrote:

Last word of high power electronics are IGCTs .
For example, see:
http://www.polovodice.cz/_files/soubory/igct.en.0805119.pdf
Anybody have used them for tesla coils already?

Dex

>You would
> be
> better off using IGBTs as a replacement for the spark gap <see
> http://wiki.4hv.org/index.php/SISG>
>
> -Phillip Slawinski
>


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