>Problem is with 20 wires, the load would never be constant enough on all=
 20 - inductance would vary,
>particularly with varying proximity to the 'victim' metal,

That is why i suggest intertwining them.  (Don=B4t know if that is the re=
igth word, though)

> so although initial current may be equal,
>changes inductance may conspire to gang up on a few of the thyristors.=20

When connected to separate caps, ther will not be very much differance (b=
ut stil some due to different pulse shape)

>Multiple thinner wires would also have a lot more inductance, limiting t=
he all-important DI/DT
>acheived.

On the contrary - given a defined total conductor area, spreading them ou=
t on several wires *lowers* inductance.  Plus, you van arrange for very s=
hort wires bu mounting SCRs and cpacitors in an ring around th ecoil, mak=
ing wires much shorter than when using only one cirquit, this makes for l=
ower resistance and inductance in the total assembly.

Spreading them out however makes exact firing more complicated.  On a Lar=
ge current MOSFET PWM, I used coaxial wire of same length to each group o=
f fets (and suitableattenuation, and firing ground separate from power ro=
und)

What can happen if a SCR fires latern than the other is that it see absol=
utely max double capacitor voltage.  To protect from that either use SCR =
that can handle that voltage, or use an antiparalell diode.

/Morgan
--
Morgan Olsson, Kivik, Sweden


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