RE: no need to short cap?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Wood by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mike.wood-at-opennw-dot-com>


Hi beans!

you mean you checked by touching it?  hey, cut that out!

having said that, I've not worked with sw caps.  But I'm still not sure you
should be prodding it to see if you get a shock.  Energy stored inna cap is
0.5 CV^2 (IIRC) and in tesla coil use, the V^2 is going to be quite big,
even if your capacitance (I'm guessing maybe 6nF for your bottle cap) is
small.

Coilers building mmcs often include bleeder resistors across each cap to
discharge them after powering down by converting the stored energy to heat.
I'd ideally choose bleeder resistors that discharge the caps rapidly enough
to prevent any energy remaining by about the time I could walk over to the
coil after shutting down, so if I need to adjust something I won't get a
nasty surprise.  I think caps without bleeder resistors can exhibit
something called dielectric memory as well - which basically means that even
a cap that's been left disconnected and has just lurked unshorted in the
shed for a while could bite the unwary.

coil safe anyway!

Mike
Wellington, NZ




Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Beans45601-at-aol-dot-com>

I have alwas read, "be sure to short out your cap after you use it". Well,
after runing my coil, i can touch my cap all i want and i get no shock. How
come? i am using a geek group SW cap with 6 bottes used.
Thanks
Adam