[TheForge] Hobo Nickels

[Grover.Richardson at gtri.gatech.edu]

Charged to 7 kV, they drop about a Volt a second (with a meter
permenantly attached across the terminals).  But they are BIG.  Model
32634, 225 uF/15 kV.
http://www.surplussales.com/Capacitors/MaxwellList.html

The ones that surprised me had been in a box in a warehouse for 2 years,
wrapped in paper.  25 kV, don't remember the size, about 10 uF or so.

If anyone is considering working with high Voltage capacitors there is
another caveat.  Many are made in sections.  Think of them like a series
of D cell batteries in a flash light.  If you short the ends, then they
go to zero Volts across the ends.  But the actual Voltage across each
cell may or may not be zero.  So when you unshort the ends, the cells
will go back up to whatever the sum of the individual cells was/is.  If
you are talking about a 12 Volt battery stack, you may get a Volt or so.
If you are talking about a 12 kV capacitor stack, you may get a kV or
so.  

If anyone needs to talk high Voltage, high power, pulsed power, this is
what I do for a living.  We can take this direct.

All the Best

-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Andrew Vida
Sent: Tuesday, June 17, 2008 4:44 PM
To: Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] Hobo Nickels



Grover.Richardson at gtri.gatech.edu wrote:

> Surplus Sales of Nebraska has some good quality capacitors.  You can
> pick up capacitors to store a megajoule of energy relatively cheaply.
> If you have a fork lift<G>.

	How long will they hold their charge?