3300µF 450V caps...

[eccerr0r]

Okay...

I scored a "small" pile of 3.3mF 450VDC(525V surge) 85°C electrolytic capacitors, looks like they are "BC" branded capacitors, looks like Vishay bought them. Now...what can I do with them. Unfortunately probably not low ESR caps else making a railgun would have been something.

½CV² with these is no joke... with one of these on the input of a psu would have a significant hold up time.

Do people normally short the terminals of such large capacitors during storage? Or probably the previous owner worried about the lurking of the evil charge sending one flying in a very un-technician-like manner?

[stj]

make an electric chair for communists - that uses a stored charge to not overload a domestic supply!


dont forget to include inrush limiting.

[redwire]

You can do the math but the energy to lift up a person a foot off the ground, is stored in one cap. How far a commie would launch... they're full of so much hot air lol.

I don't short electrolytics in storage, I find they do go up to a few volts at their natural half-cell potential which keeps the oxide alive.
But dielectric absorption could mean the caps float up to HV a short time after use. You have to check, especially after reforming.
I have oil-filled low value like 0.05uF 20kV HV caps that I store shorted because they are known to pick up stray static electricity and bite. This is common knowledge from back in the old days of radio transmitter work.

As for an application for the caps- I've seen those values in motor drives and electro-fishers. Charge to 400VDC and discharge into fishnets to catch them.
In tube audio amplifiers they are pretty big, 3,300uF is 5-10X what is normally used.

[stj]

ah yes, the self charging cap thing.
i have noticed that, i dont think it's "static"
you get the same effect from nimh batteries.

what do they have in common?
a long electrode rolled up.

i think they are charging from either what tesla called the "ether" or from tv/radio/radar or other emmited energy

[PeteS in CA]

Maybe you could use them as hand weights for weight training?

[eccerr0r]

They do have some heft per unit but not really that much, seen bigger.
Speaking of weight, technically they have a significant amount of aluminum in them, though the electrolyte probably contributes to total mass... Wonder what the aluminum scrap value is,...

[redwire]

In the repair shop one tech would charge caps to 400VDC in the Heathkit and toss them at you yelling "catch!". I let them fall on the ground but a few people got nailed.

[stj]

fuckers,
if anybody had tried that with me i would use the same trick with pre-heated soldering tips!
grab one with the longnose pliers and "hey dickhead - CATCH"

[eccerr0r]

how many µF is needed to not cause damage and make a difference ?

I think a 3.3mF could cause significant damage... granted you have to get unlucky in one direction, most of the cap is insulated...

Then again ... add screws to it and have it protrude out more...

(hmm... speaking of these screw terminal caps, most of the ones I've dealt with use #10-32, but now these 3.3mF use ¼"-28 despite not being low ESR AFAIK.)

[stj]

last caps with threaded studs i bought used M8 metric