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

["Dex Dexter" <dexterlabs@xxxxxxxxxxx>]

Well,"ABB" (big company in Europe) manufactures
HV IGCTs for variety of their needs.
If they sell them separately or not,I don't
know.Yes,switching losses are higher than of
that IGBTs,and you need 2 IGCTs to replace 1 IGBT
as tesla coil primary switch.
Switching times of IGCTs are improving.
Fastest times today are couple of microseconds.
VA rating of big  IGCTs seems to be much
higher than rating of the biggest HV IGBT.
Perhaps if some coilers prepare monster  
coil project good to know :-)
Few more comparations to read about:
 http://fab.cba.mit.edu/classes/MIT/961.04/topics/power_electronics.pdf

Dex


--- pbbrodie@xxxxxxxxxxxxx wrote:

From: "Paul Brodie" <pbbrodie@xxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: Re: [TCML] spark gap substitute...?
Date: Wed, 27 Jan 2010 18:15:45 -0500

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



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