what are 7mf 1500 volt caps good for?

Ive got around a dozen 7mf 1500 volt capacitors. What are they good for?
Anyone need them?
Gunner
It's not unwise to remember that Mother Nature is essentially a
murderous, sneakly, promiscuous bitch who has been trying to kill you since your conception.
Eventually she will succeed, perhaps with the help of your fellow man.
Life consists in putting off the inevitable as long as possible and taking what good and joy you can before her success.
Whether you attribute that situation to evolutionary forces, a fallen nature after Adam and Eve screwed the pooch, or whatever, it's no less true.
Be friendly, pleasant, unaggressive, and honest toward all and be prepared to ignore, avoid, or even kill anyone who is otherwise toward you. Being ready doesn't mean eager, just ready. What true friends are found in life will undestand and accept that fundamental rule of human interaction." John Husvar
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7 "MFD" (MicroFaraD), "mF" (miliFarad) or F (micro-Farad)?
Might be useful for really high voltage motors, although even the beefiest 3 phase I've seen isn't that high. Filter a high voltage power supply... for that induction supply I'm going to need around oh, geez 470uF 2500V wouldn't hurt...yum, 1.5kJ... fortunately it's a ripple-tolerant application! But I already have a few caps from the original light power supply so I'm not interested.
Couldn't hurt to throw it on e-bay and add keywords like tesla coil and such. :)
Tim
-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms
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Tim Williams wrote:

If they can be picked up by hand, I suspect they aren't 0.007 Farad 1500V caps (i.e. milliFarad). Probably 7 micro farad.
Steve
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wrote:

They are silver cans, rectangular in shape with rounded sides, about 8" tall, by 1.25 or so thick and 4" wide.
They say 7 MF 1500 volt. Internal resistor
They look like much larger versions of the rectangular ones in this picture:
http://www.capacitorindustries.com/images/CBB65web.jpg
Gunner
It's not unwise to remember that Mother Nature is essentially a murderous, sneakly, promiscuous bitch who has been trying to kill you since your conception.
Eventually she will succeed, perhaps with the help of your fellow man.
Life consists in putting off the inevitable as long as possible and taking what good and joy you can before her success.
Whether you attribute that situation to evolutionary forces, a fallen nature after Adam and Eve screwed the pooch, or whatever, it's no less true.
Be friendly, pleasant, unaggressive, and honest toward all and be prepared to ignore, avoid, or even kill anyone who is otherwise toward you. Being ready doesn't mean eager, just ready. What true friends are found in life will undestand and accept that fundamental rule of human interaction." John Husvar
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    [ ... ]

    [ ... ]

    [ ... ]

    *Way* too small for 7 mF -- almost certainly 7 uF.
    Can you find anything which might be a date code on them? the "7 MF" designation sounds really old.
    I wonder about the internal resistor. It could either be a parallel resistor to safely discharge it when the power source goes away, or a series resistor to limit the current available from discharge.
    If the former, it could be used for serious strobe lights -- especially if you parallel up a bactch of them.
    If the latter (series resistor) I guess that it could be used for high-voltage filtering (though it would not be as good as one without the series resistor for fast changing loads).
    However -- it the caps are stored without a wire connecting the terminals (which is common on high-voltage caps) then I think that we can assume that it is a parallel internal resistor for safely discharging the caps.
    So -- think electronic flash units -- including those to optically pump a Nd-YAG laser.
    Enjoy,         DoN.
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Some manufacturers never really caught on to the appropriate nomenclature.

The resistor is most likely to prevent self-charging. My old boss used to store these with a wire shunt across the terminals - he claimed that cosmic rays would charge them up over time.
As for the best use? As already mentioned, you just wave them around (working end pointing outward of course) at your buddies. Doesn't matter if you charged them up or not, you get a great reaction either way!
Jim
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---------------------------------------------------- If they are old oil filled with PCB caps that is a big no-no! They should be properly disposed of. Donald Warner
Don't let the facts interfere with your prejudices -------------------------------------------------------------------------
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be
Eheh, what an interesting sig. Has it even been proven beyond a doubt that PCB's are carcinogenic anyway?
Tim
-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms
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wrote:

They say " flammable liquid, no pcbs".
Gunner
It's not unwise to remember that Mother Nature is essentially a murderous, sneakly, promiscuous bitch who has been trying to kill you since your conception.
Eventually she will succeed, perhaps with the help of your fellow man.
Life consists in putting off the inevitable as long as possible and taking what good and joy you can before her success.
Whether you attribute that situation to evolutionary forces, a fallen nature after Adam and Eve screwed the pooch, or whatever, it's no less true.
Be friendly, pleasant, unaggressive, and honest toward all and be prepared to ignore, avoid, or even kill anyone who is otherwise toward you. Being ready doesn't mean eager, just ready. What true friends are found in life will undestand and accept that fundamental rule of human interaction." John Husvar
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Ok - we decided they were 7uf high voltage. Put two in parallel and you have 14 uf at the same voltage. Two in series and 3.5uf at double voltage.
In parallel they simply add. 10ea. = 70uf.
They could be used in a voltage doubler or t rippler... for a GM tube ?
Martin
Gunner wrote:

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Charge one up, sneak-up behind a loved one and...

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http://groups.yahoo.com/group/Offenhauser
Is a link for a support group for machining a 1/4 scale running Offenhauser 270 engine.
Les
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On Sun, 29 Aug 2004 16:29:13 GMT, "Tom Gardner"

Loved one? Not for long.....
Hummm better mousetrap ideas spring to mind....<G>
Gunner

It's not unwise to remember that Mother Nature is essentially a murderous, sneakly, promiscuous bitch who has been trying to kill you since your conception.
Eventually she will succeed, perhaps with the help of your fellow man.
Life consists in putting off the inevitable as long as possible and taking what good and joy you can before her success.
Whether you attribute that situation to evolutionary forces, a fallen nature after Adam and Eve screwed the pooch, or whatever, it's no less true.
Be friendly, pleasant, unaggressive, and honest toward all and be prepared to ignore, avoid, or even kill anyone who is otherwise toward you. Being ready doesn't mean eager, just ready. What true friends are found in life will undestand and accept that fundamental rule of human interaction." John Husvar
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Kill them stone dead?
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wrote:

Nobody has a sence of humor anymore! I was going to say sneak up on the barky dog but I would have torches and pitchforks at my door. I always sneak-up on Fritz (mini schnauser) after he gets shaved and while he is asleep in my chair, I put a cold can of pop on his bare belly. In retaliation, he takes a running leap at my sleeping form in the same chair. He's still my best bud even when I read Schnauser recipies to him, and he jumps into my lap and farts and leaves.
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Seriously though, there is enough energy there to kill. Maybe not always, but not infrequently.
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My gut says no kill. Somebody with more math skill will have to work this out.
Lets see:
1 farrad= 1 coulomemp 7 uF=.007amp at 1500v I think I've been hit with more from a sparkplug wire on many occasions and I was only mentally damaged.

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1 A = 1C/s and 1F = 1C/V!!!! If released in .001s, you're back to 7 amps (average... it's an exponential curve, so starts at 14A in the very first nanoseconds, falls to 7A at 1ms, then keeps falling past there towards zero at an infinite time period).
Besides, it depends on the body's resistance. 1500V has been known to be much more fatal than 120V...
Tim
-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms
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On Mon, 30 Aug 2004 17:53:30 GMT, the renowned "Tom Gardner"

energy = C*V^2/2 = 8J. A defibrillator delivers a couple of dozen to a couple of hundred J, so I would not bet on it being fatal for a normal person unless it makes you fall off a ladder into a wood chipper or something.
Best regards, Spehro Pefhany
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Err, no. 1 Farad = 1 Coulomb/V. 1 amp, 1F = 1V/s.

Discharging it all in one second gives .015A. However, at high voltage, the body has a resistance of some 500 ohms. This means that the current starts at 3A or more.
So, it'll discharge in about 2ms.

Spark plug wires will not put out more than a few tens of milliamps, at best.
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