Re: Newark ebay capacitor: primary tank capacitor?

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

Original poster: "Virtualgod" <mike.marcum-at-zoomtown-dot-com> 

The 10 kv ones? Usually doorknobs are rated dc or dc peak volts. For 4 mots
(~8kvac) you would need at least 24 kvdc worth. And mots put out about
300-500 mA. Assuming 500 mA, 60hz, and a LTR static gap (probably a rotary
would be needed with that much current), that equals .2487 uF, which would
probably mean a single turn primary (or less, which would problem) unless
your coil is huge. You would need 3 in series (round up to 30kv), which cuts
the capacitance down to 1100pF x 226 sets these (or less, depends how much
you limit the mot current). 678 of these would be very expensive and would
be a major pain just to put them all together. It would take 104 (8series
x13parallel array) of the 942c's (about $260 worth). Of course it would take
less if you limit the mots more.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, February 25, 2004 1:24 PM
Subject: Re: Newark ebay capacitor: primary tank capacitor?


 > Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
 >
 > Gah forgot to say, would 10 of the 3300 pf, or 3.3 nF, in paralell be
 > suitable for a 3 inch coil with a 4 pack mot supply?
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Wednesday, February 25, 2004 8:27 AM
 > Subject: Re: Newark ebay capacitor: primary tank capacitor?
 >
 >
 >  > Original poster: "Virtualgod" <mike.marcum-at-zoomtown-dot-com>
 >  >
 >  > With doorknob types, it's hit or miss. The ones that are not rated for
rf
 >  > will overheat and die. Not sure if there is a way to tell just by
looking
 > at
 >  > them. Usually I've seen a seen a dozen or so 30-40kv ones in parallel
to
 > get
 >  > the capacitance needed. Considering the cost of that (~$10-20 each),
 > better
 >  > off getting 942c's where you know what you are getting.
 >  > ----- Original Message -----
 >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  > To: <tesla-at-pupman-dot-com>
 >  > Sent: Tuesday, February 24, 2004 11:22 PM
 >  > Subject: Re: Newark ebay capacitor: primary tank capacitor?
 >  >
 >  >
 >  >  > Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
 >  >  >
 >  >  > Alright ,what about these caps:
 >  >  >
 >  >  > http://cgi.ebay-dot-com/ws/eBayISAPI.dll?ViewItem&item=2597981535
 >  >  >
 >  >  > sry if I'm being annoying.
 >  >  >
 >  >  > ---Eric
 >  >  > ----- Original Message -----
 >  >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  >  > To: <tesla-at-pupman-dot-com>
 >  >  > Sent: Tuesday, February 24, 2004 5:51 PM
 >  >  > Subject: Re: Newark ebay capacitor: primary tank capacitor?
 >  >  >
 >  >  >
 >  >  >  > Original poster: Bert Hickman <bert.hickman-at-aquila-dot-net>
 >  >  >  >
 >  >  >  > Tesla list wrote:
 >  >  >  > >Original poster: "Hydrogen18" <hydrogen18-at-hydrogen18-dot-com>
 >  >  >  >
 >  >  >
 >  >
 >
 >http://cgi.ebay-dot-com/ws/eBayISAPI.dll?ViewItem&item=2597989262&category=4662
 >  >  >  > >could that capacitor(in series obviously) handle the stresses of
 >  > primary
 >  >  >  > >tank capacitor duties? Also, can some1 point me to reference so
I
 > can
 >  >  >  > >convert uf to nf, pf and uf, and so on? I know 10^-9 is nano and
 > 10^-6
 >  > is
 >  >  >  > >micro but that doesnt mean much to a mid class geometry student.
 >  >  >  > >
 >  >  >  > >.
 >  >  >  >
 >  >  >  > Dear (what's your name?),
 >  >  >  >
 >  >  >  > These caps are Mylar. Because they are very lossy under RF use
and
 > the
 >  >  >  > package does not allow for "graceful" expansion, they tend to
become
 >  > oily
 >  >  >  > firecrackers when used in Tesla Coil tank circuits. They are
usable
 >  > only
 >  >  > as
 >  >  >  > DC filter caps, in voltage doubler circuits, or in low pulse rate
 >  > (non-RF)
 >  >  >  > applications.  :^(
 >  >  >  >
 >  >  >  > 1 uF = 1,000 nF = 1,000,000 pF
 >  >  >  > 1 nF = 0.001 uF = 1,000 pF
 >  >  >  > 1 pF = 0.001 nF = 0.000001 uF
 >  >  >  >
 >  >  >  > These caps are 0.25 uF = 250 nF = 250,000 pF
 >  >  >  >
 >  >  >  > Best regards,
 >  >  >  >
 >  >  >  > -- Bert --
 >  >  >  > --
 >  >  >  >
 >  >  >  >
 >  >  >  >
 >  >
 >  >
 >
 >