Re: Awesome Quarter Shrinking Capacitors on EBAY

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

Almost certainly MFD = 1E-6 Farad.. i.e. microfarad.  millifarad is almost
never used as a unit.. microfarad, nanofarad, picofarad and micromicrofarad
I've seen..

Oil filled metal can really starts to look like 4 microfarads at 4 kV...

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, October 07, 2003 8:04 PM
Subject: Re: Awesome Quarter Shrinking Capacitors on EBAY


 > Original poster: John <fireba8104-at-yahoo-dot-com>
 >
 > Hello,
 > This capacitor is not a electrolytic or a cap bank.
 > It is in an oil filled metal can with large white ceramic insulators.
 > I am not sure what kind of dielectric, but I believe it to be a type of
 > plastic.
 > The exact wording on the side of the cap reads as follows:
 > KN128
 > 4MFD
 > 4000VAC
 > I was unsure as to weather this was Milli or Micro. My hopes were
confirmed
 > when I asked the man who gave it to me, a professional electrical
 > engineer.(0.004). I think it's from
 > <http://www.plasticcapacitors-dot-com/>http://www.plasticcapacitors-dot-com, after
 > all he is a customer.
 > Cheers,
 > John
 >
 > Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Jim Lux"
 >
 > Indeed.. you're right, I missed the missing u... But, then, a 4000 uF cap
at
 > 4kVAC rating.. Hmmm. maybe in the form factor cited, but not going to be a
 > high current device. Almost certainly a stack of electrolytics, which then
 > casts doubt on the VAC rating, as opposed to VDC...
 > Say, then, two 8000 uF 4kV DC electrolytics in series? I've got some
 > 250,000 uF 400 V electrolytics in a form factor comparable to what's
 > quoted.. But, to get 4 kV, means 10 in series, for 25 uF... For 4kV AC,
 > that's 12 uF, and would be a LOT bigger than a Simpson, but, not orders of
 > magnitude.
 >
 >
 > I think though, that we could agree that this is NOT something with high
 > pulse current capability.
 >
 >
 > ----- Original Message -----
 > From: "Tesla list"
 > To:
 > Sent: Fri! day, October 03, 2003 8:35 PM
 > Subject: Re: Awesome Quarter Shrinking Capacitors on EBAY
 >
 >
 >  > Original poster: Mddeming-at-aol-dot-com
 >  >
 >  > In a message dated 10/3/03 6:42:16 PM Eastern Daylight Time,
 >  > tesla-at-pupman-dot-com writes:
 >  > Original poster: Jim Lux
 >  >
 >  > At 03:47 PM 10/3/2003 -0600, you wrote:
 >  > >Original poster: John
 >  > >I have a 0.004F cap rated at 4000VAC (32,000 jolues) that is only a
bit
 >  > >smaller than my simpson 260 multimeter.
 >  >
 >  > That's 32 millijoules, not 32kJ... .004 * 4*4/2 = 32E-3...
 >  >
 >  > Look again. he said 0.004F NOT .004 uF! If he's right, your calculation
is
 >  > off by 10e6
 >  >
 >  > Matt D.
 >  >
 >
 >
 >