I recently acquired a few interesting large capacitors.
5 that are 7,900 uf 350WVDC
2 that are 490,000 uf 35 WVDC (max surge 40V)

I am hoping they are not blown, I think they were replaced because of an upgrade in which the replacements have to be larger so these were discarded.

No need for warnings... these are seriously dangerous toys when charged.

to give a nice feel for how different.
a disposable camera at max is around 160uf or so (350volts)
A commercial flash unit for a DSLR can be 10 times as much so that you can take many pictures before waiting for a charge. 1600uf

you would need around 3000 disposable camera capacitors to match the uf of just one of the large caps... (but voltages are not equal).

discharge that with a screwdriver and it will not be pleasant...

I wonder what great hobby project one can use one or more of them for.

and just to limit the list to something a bit more reasonable
(as I live in an apartment)

no sasquatch stunners
no rail guns
no tesla coils
no emp pulse
no Jacobs ladder (already done it)
no shrinking coins...

ok.. I know... took out all the best fun ones...
but really, how suitable are those for an apartment?

I also have a collection of some motorized micrometers
so what I thought of was using a 1amp laser, and pulse it at much higher power, and perhaps make a micro CNC machine.
[my day job is an applications developer for research computing so the software and such is not the hard part for me, the hardware and such is more so]

this CNC would not be able to work on anything larger than a postage stamp given the micrometer travel distance.

how long could one run led lights off of something like that?
use the cap as a battery with a high cycle life for some solar cells I have laying around?

I have some weird spare parts that are always looking for a project.
a nice collection of small vacuum arc gaps...

well, be interesting to hear what comes up
if ideas are interesting I may take a picture of the strangest parts for doing things and then see what comes up... but no promises, life has been very busy lately..

 

Suggestions:

1. Spot welder.
2. Door stop.

Number 2 is the safest for an apartment, but number 1 would be more fun. I built one 20 years ago using two 47,000uF (industrial grade the size of a coke can) in parallel and a heavy duty SCR to dump the charge. Worked well for spot welding steel sheets together.

If the caps are old they should be formed up before using. If they will be use in a high current discharge application then inclose them in a metal box or chassis in case they explode.

What current rating do they have?
What is the physica size? (to get an idea of current rating)

Play Safe,
Ifixit

 

A spot welder is a really good suggestion..

dangerous is ok... nothing in life is safe and i have done some prior high voltage projects...

i do not like the paper weight idea..


the Capacitors documentation is here
http://www.cde.com/catalogs/DCMC.pdf

as i said, its 490,000 (one more zero than your mention)
490F technically...

this one is 35 WVDC max surge 40vdc

its 3.5 inches in diameter, the size of a fosters beer...

i have a 35 amp/10 volts transformer for 120 volts
that would make a hell of a welder too?

how bout a super low frequency oscillator with a 10 year cycle.. ha ha

they have no continuity (not shorted)
but my meter only goes up to 600uf

i am leaning towards the cutting lazer... somewhere in here i have a half inch thick orange glass plate..
makes a nice laser sheild for blue lasers of moderate strength...

a fly zaper from hell?

 

They are 0.49 Farads not 490 Farads. There is 1 million microfarads in 1 Farad and your caps are 490,000 microfarads. To roughfully measure the capacity you could charge them through a 10Ω resistor from a voltage source and measure the time it takes to get to 63% of the source voltage (TC). Don't forget to discharge using the 10Ω resistor.

TC = R x C, so T = 10Ω x 490,000uF = 4.9 seconds, or one tenth of a second for every 10,000uF.

The spec doesn't say they can be used in a high discharge current application, but would likely work for occasional use. The ESR is only 3.5 milliohms, so a screw driver short from 35V would yield 10,000 Amps so don't do that.

This is way more than needed for most spot welding. Using an SCR though a length of wire would limit that. Having 100 to 200 milliohms in series would be good.

Hopefully a better idea will pop up.

Regards,
Ifixit

 

thanks for setting me straight on the farads..
and my post pointed out that a screwdriver is a very bad idea
I used a ten meg ohm ceramic resistor to make sure they were discharged

and your comment as to 10,000 amps confirms it would be the bug zapper from hell...

I think I will probably use one in a led lighting application with solar cells and go for a lot slower discharge than 10k A. I wonder how long 10 white leds would stay lit from a full charge...

other than slow discharge as a high cycle capacity battery, not much you can do.... the worlds funkiest joule thief....

 

I wonder how long 10 white leds would stay lit from a full charge...

Not very long. Do the math. A 470,000μF capacitor charged to 3V might power a standard LED drawing 20mA for about 30 seconds. The LED just gets progressively dimmer.

 

Nice blue paperweights so far...





Aluminum capacitors target solar applications

Ismini Scouras
11/8/2012 11:09 AM EST

Vishay Intertechnology Inc. announced a new series of snap-in power aluminum capacitors with a rated voltage of 500 V at 50 °C and a category voltage of 450 V at 105 °C. Targeted at solar applications, where the highest voltage is present under no load conditions, the 193 PUR-SI Solar devices also feature a long useful life and rated ripple current up to 2.52 A at + 105 °C and 100 Hz.



Featuring a cylindrical aluminum case with a pressure relief valve, insulated with a blue sleeve, the new 193 PUR-SI Solar capacitors are available in five case sizes ranging from 35 mm by 30 mm to 35 mm by 60 mm. At 500 V, the devices feature a maximum operating temperature to + 50 °C and useful life of 5,000 hours (no ripple current applied). At 450 V the maximum temperature can be extended to + 105 °C, and the useful life is 6,000 hours.



As polarized aluminum electrolytic capacitors with a non-solid electrolyte, the 193 PUR-SI Solar devices are suited for smoothing, filtering, and energy storage in pulsed power applications. End products include solar PV inverters, industrial motor controls, and power supplies.



Device Specification Table:
Case size (D x L in mm)
35 x 30 to 35 x 60
Capacitance range at 500 V
220 µF to 560 µF
Tolerance
± 20 %
Ripple current at 100 Hz and + 105 °C
1.35 A to 2.52 A
Rated voltage
500 V
Category voltage
450 V
Rated temperature range
- 40 °C to + 50 °C
Category temperature range
- 40 °C to + 105 °C
Useful life at 500 V, + 50 °C
5,000 hours
Useful life at 450 V, + 105 °C
6,000 hours
Shelf life at 0 V, + 105 °C
1,000 hours
Max. ESR at 100 Hz
350 mΩ to 900 mΩ
Max. impedance at 10 kHz
250 mΩ to 600 mΩ
Sectional specification
IEC 60384-4/EN130300
Climatic category IEC 60068
40/105/56

Pricing: For U.S. delivery only starts at $5.50 per piece.
Availability: Samples and production quantities of the 193 PUR-SI Solar series capacitors are available now, with lead times of eight to 14 weeks.