Re: [TCML] IGBT?

[Finn Hammer <f-h@xxxx>]

Hold your horses, Jay.
One single CM600 is good for 5 feet of solid connecting spark, as seen
here:

http://www.youtube.com/watch?v=vK17-CoB7LE [http://www.youtube.com/watch?v=vK17-CoB7LE]

Cheeers, Finn Hammer

----- Original meddelelse -----

> Fra: jhowson4@xxxxxxxxxxx
> Til: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
> Dato: Tor, 22. sep 2011 03:36
> Emne: Re: [TCML] IGBT?
> 
> Gotchyea, the rise over fall time makes perfect sense now. Thank you
> for the link.
> 
> Well I guess I will have to get some IGBTs and test them out, when
> the time comes. =)
> But having bricks would indeed be much nicer, just from looking at
> them I can see that they are rugged.
> 
> Does anyone have any of the cm600's or close to that for sale?
> 
> Thanks,
> John "Jay" Howson IV
> 
> ----- Original Message -----
> From: "Finn Hammer" <f-h@xxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Wednesday, September 21, 2011 2:42:48 AM
> Subject: Re: [TCML] IGBT?
> 
> About how much current you can push trough a semiconductor.
> 
> Manufacturers test theit devices to a level where they are willing to
> back them up with at least their name and reputation. Not saying thay
> will ever replace them for you.
> In tesla hobby community, it has become current practice to test the
> devices to destruction, or in the case as with real professionals
> like
> Terry Fritz, to just under destruction.
> I recall seing scope shots of the voltage drop across these IGBT´s at
> a
> point where they started to drift into a situation where their
> resistance
> would rise, and heat is generated violently. As far as I understand,
> the
> devices are forced to turn off ever so slightly, because the gate
> voltage
> is lowered due to some paracitic capacitance acting on the rising
> current, and therefore cannot be counteracted upon.
> The device is going out of saturation, I believe is the term applying
> to
> that situation.
> So to the average joe, like myself, it is "suck it and see" and I
> have
> successfully driven CM600´s beyond the 8kA mark without blowing tham
> up.
> But no telling how long they will last.
> 
> I do have one coil running now in museum duty on a daily basis for
> the
> 6th year in a row, and if I was more scientifically inclined, I guess
> I
> would calculate the primary current in it, to support my words with
> hard
> data.
> 
> So this didn´t help much, but then, with all due respect, you can´t
> expect detailed help before there is a committed design to select
> devices
> against. I would suggest bricks anytime, though, coz thay are
> rugged-fer
> sure.
> 
> Now the trisils:
> When you get to a design that is actually going to be built, I will
> find
> a nice little program that Terry wrote back then, it calculates, and
> plots, the current trough trisils and IGBT, depending on the voltage,
> primary inductance and the size of the tank cap.
> The current trough the trisils can only rise to so much due to the LC
> time constant, and the turn on time of the IGBT, so these are the
> parameters you play with.
> The Trisils just short the voltage across the IGBT for long enough to
> turn them on, so that they themselves can short out, and take over.
> As
> soon as the voltage is kept low by the IGBT´s, the trisils will
> recover
> and be armed and ready for the next shot.
> The 10/1000 is a standard lightning related pulse, it should be
> gooogleable.
> Ok, just did:
> It describes a pulse that rises in 10uS and decays in 1000uS. That is
> a
> very wide pulse, and in radio frequency the device will be able to
> tolerate much higher peak curents.
> http://www.semtech.com/images/datasheet/si96-03_ag.pdf
> [http://www.semtech.com/images/datasheet/si96-03_ag.pdf]
> 
> Cheers, Finn Hammer
> ----- Original meddelelse -----
> 
> > Fra: jhowson4@xxxxxxxxxxx
> > Til: tesla list <tesla@xxxxxxxxxx>
> > Dato: Ons, 21. sep 2011 02:03
> > Emne: [TCML] IGBT?
> >
> > Hello all,
> >
> > I am attempting to figure out how to properly choose an IGBT for a
> > SISG board.
> > Not sure if I will be building one yet, but more of a learning and
> > trying to figure everything out kind of thing. so I have been using
> > my current coil as a base design, just for the purposes of figuring
> > this out on paper.
> >
> > The schematic calls for an IRGPS60B120KDP
> > But the current to pulse frequency characteristics are not listed
> in
> > the datasheet.
> >
> > How does one determine if the IGBT will be acceptable for my
> > particular coil set up?
> > Java TC tells me that my primary current is close to 400 amps peak
> > current (not that the coil that might be built would have that
> > primary current)
> > I read some where (wish I remembered where) that these were fine up
> > to an 800amp primary peak current...is that way off base, and if
> not
> > where did that number come from?
> >
> >
> > I am having a similar issue with the SIDACs which I have been
> > informed the proper replacement is called a TRISIL
> > specifically this one
> >
> http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00001359.pdf
> >
> > Once again I am not sure why. Probably because I don't understand
> the
> > format. Like in the section labeled repetitive peak pulse current
> the
> > value is defined as 10/1000 us being 30A at first i though that it
> > was a simple fraction expressing that it could handle a 30 amp
> pulse
> > every 10ns, but apparently that is not right per a random forum
> post
> > I found... somewhere... So what exactly does 10/1000 mean?
> >
> >
> >
> > Thank you to anyone willing to help me learn,
> > John "Jay" Howson IV
> >
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
> 
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