TU56/TC11 restoration - VARIAC question

[der Mouse]

> Important to remember when charging capacitors up is that they then
> have a fairly high 'instantaneous' current capability.

Very true.  There's a reason railgun power supplies tend to be
capacitor banks which are slowly charged and very quickly discharged.
(Railguns, at least conventional railguns, demand very high current for
a very short time - mega-amps for milliseconds.)

> You might 'melt' whatever shorting item you use if you just crowbar
> it, and the hot metal can burn.

Right.  There's a reason high-power computer supplies have labels
showing slashed-circle "no!" signs over watches and rings: they are
entirely capable of turning a metallic object like a ring or watch
red-hot right on your hand.  If you're really unlucky, it can
simultaneously spot-weld it to whatever it touched and fail to overload
trip (.1 ohm contact resistance at 5 volts draws only 250 watts, which
is not that much to an even moderately beefy computer power supply).

I once deliberately tripped a mains breaker by shorting hot to ground
with a screwdriver.  It made an impressive crack! sound, and even more
impressive was that the screwdriver shaft was vaporized half through -
probably a couple of grams of steel gone.  Not something I'm going to
repeat; it gave me a good deal more respect for such things.

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