capacitor bus bar

[Tywaser]

I have 10 63000mfd 30 volt capacitors that will be charged to 28 volts, then discharged by a short circuit creating a shower of sparks or a low resistance such as a small spring which should glow white hot and break when touched to the bas bar. this capacitor bank is not too big but i live in an apartment. I was wondering if I should use copper bus bars instead of steel because of its lower resistance? how much difference would it make on the amount of sparks? (I like sparks)

 

[GreenGiant]

First off you should be doing this outside or in a bunker not near anything flammable

Second where the heck did you get 10 63F caps?

Third you would probably be better off with copper since the melting point is lower there for it will turn into "sparks" faster and more easily

Overall the effect that you are trying to achieve doesn't sound like something that you can do with a capacitor, or a capacitor bank, caps usually just discharge very fast creating a loud pop and some sparks from the contact, but its over so fast that it doesn't cause things to get overly hot...

I wouldn't recommend fooling around with this stuff without experience and other around to spot you if you short something... this is quite dangerous

 

[jackorocko]

Oh I think it will get quite hot. In fact with that capacity I bet you will make some molten metal. The steel bars will provide more resistance and that will create a larger voltage drop across the bars. Creating more heat and less power being delivered to the load.

The question is why?

 

[Tywaser]

oops

i meant 63000 uf. i have seen other people use these terms interchangeably. i am well experienced with using caps and i do use these outside but still 'at' the apartment. i would never do this near anything flamable or use a 63f cap for short circuit because it might melt the terminals on the cap. the 63000uf (not f) caps cost me $29 each. they are sprague powerlytic cgs caps.

 

[(*steve*)]

If I were you, I would get the datasheets for those capacitors and see what currents they're rated for. You may damage them by discharging them too fast.

There are capacitors designed especially for high current discharge (used in xenon flash applications) and these might be safer... or more dangerous...

 

[Tywaser]

They shouldn't

i have a mallory cgs 43000 uf 30 volt cap that I frequently charge to 27 volts and discharge in a short circuit. the cap has survived over 10000 cycles and it's performance has not decreased. The 10 cap i have are the same price per piece and are around the same size. I have never had a cap fail or be damaged by a short circuit. In fact I have used a tiny 6.3 volt 2200uf cap with a 9 volt battery and then shorted it. I have even managed 15 volts across it for several 100 snaps before it split open. Why would this one fail?

 

[(*steve*)]

Because as you get to higher and higher energy levels, you risk bigger and bigger bangs.

Sure, the only problem with your 43mF 30V cap may be heating, and your duty cycle may be so low that it never poses a problem.

However, at some point, you may find a capacitor where the instantaneous heating in internal conductors is sufficient to damage the electrolyte, or even melt the wires.

I'm just providing you with sound advice, I can't force you to heed it. But if something does happen... You were warned.