Come on - slowly ramp up the voltage to 22kv - hold steady - have cap in a cage
box - in case it blows - and then ramp the voltage down. The supply
will draw the charge off the cap. Just remember, if they blow, the case blows...

Now if you want to measure the capacitance at some high voltage - t=RC
time (seconds) = resistance times capacitance. 1t = 66.6% voltage.

Odds are they are just surplus.

Martin

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH & Endowment Member
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member


Ignoramus27088 wrote:
Got myself some capacitors for $10 apiece.

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7603382621

The specs are 22 kV, 1 uF, discharge capacitor. See

http://igor.chudov.com/tmp/cap.jpg

The seller was wrong in describing them as 22 VOLT capacitors. They
are 22 KILO volt capacitors. (the seller is Fermilab).

They are similar to this one:

http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7598631638

but have twice more capacitance.

Anyway, here is my question. I have a 9 kV DC power supply. (a
Franceformer). How can I safely test these caps before selling
them. At 22 kV, they can store about as much energy as a .22 bullet,
according to my calculations.

It would be less at 9 kV, but still, obviously, very deadly.

So. What is a safe way to charge them, verify that they hold the
charge, and then DIScharge them at 9 kV.

i


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On Thu, 30 Mar 2006 20:55:59 -0600, "Martin H. Eastburn"
Gave us:


Odds are they are just surplus.

More likely, they are change outs. Maxwell caps are only rated for
a specific number of charge/discharge cycles. After that, expensive,
tightly controlled lab environments want new caps so they know exactly
how much energy they are working with on each stroke of the bank.