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Hi! I am building an RLC circuit to heat up an alloy witht eh capacitive discharge current. I will be using an SCR or a GTO to time discharge starting. I may have 3 or 4 capacitance branches in parallel as i need high power discharge. What kind of trigger circuit should if use if I use GTO or an SCR? Could anyone guide me to an online store form where i can buy the semiconductor switches and the firing circuits.. The non repetitive current rating of the thyristor would be around 30kA and max con state current rise rate would be around 300 A per micro seconds.

Following is the specification of the GTO which suits my purpose http://5scomponents.thomasnet.com/asset/5SGA-30J2501_5SYA1213-02Jan-05.pdf

Try googling for:

thyristor scr gto gate trigger circuits

and in particular see:

http://books.google.co.uk/books?id=072rwRgFpcgC&pg=PA407&lpg=PA407&dq=scr+gto+gate+trigger+circuits&source=bl&ots=o7GexPOp8-&sig=m8jmMX-JYA0ZOv5KeEDsTvybliQ&hl=en&sa=X&ei=cU_XUcKVFo6V0QXVvYDIBQ&ved=0CDsQ6AEwAg#v=onepage&q=scr%20gto%20gate%20trigger%20circuits&f=false

Thanx for the reply. I am bit confused about the firing. What shall i use to trigger? a gate driver or a pulse generator as i have to trigger the GTO only once for the capacitance discharge and then turn it off. And where to but it from?

If you are dealing with such huge and hence potentially dangerous currents then you must properly understand what you are doing before you attempt build anything.

You will have to read widely on the subject of thyristor, SCR and GTO gate driving and suitable driver circuits.

Advice given here based on using CL as a simulation or design tool would at best be inadequate. At worst it could be catastrophic.

You will have to look up applications notes and design notes from the device manufacturers (they are after all the people who know about such devices).

Companies such as ST, OnSemi, ABB (who supply the parts you quote), Mitsubishi, Semikron are places to start.

It may be possible to trigger a GTO directly from a pulse generator but it is equally possible that it may supply insufficicnet gate drive current to properly turn the GTO on and result in - potentially explosive - destruction of the GTO and/or the pulse generator.

Sorry but at 30kA, this is not something you play at.

You design it.

And you design it right.

:)