RE: Please help with capacitor

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

Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com> 


I believe the staple of Richard Hull's magnifiers were 0.018uF
capacitors.  He used two in series (equidrive) for
most of his magnifier designs up to 34.5kV.  ALthough, I don't have more
specific information other than what I gathered from his notes and
videos.

He does have a great video however on how to construct some very nicely
built rolled capacitors.

Dan


 > Dan,
 >
 > I have made several rolled poly caps as well, many years ago
 > when I first
 > got into coiling.  You certainly can make rolled poly caps that will
 > survive and work well in service.  If adequately designed,
 > they take up a
 > lot of room, require thick dielectric layers (or several in
 > series) and
 > don't produce many microfarads at our voltage level per cubic
 > foot - if you
 > know what I mean.  I started out with one dielectric layer of
 > .0625".  Two
 > of these worked well at 12 kv rms when used in series.  Both
 > failed when
 > used in parallel at 12 kv.  I rebuilt one with two layers of
 > .065 poly and
 > seems bullit proof but is low on capacitance.  My opinion is
 > 4 layers of
 > .020" poly or 3 layers of .030" poly is required to work at
 > 12 kv.  I would
 > question the reliability at 15 kv.
 >
 > Ed Sonderman
 >
 > >Original poster: dhmccauley-at-spacecatlighting-dot-com
 > >
 > >I might have to disagree.  Richard Hull was using rolled
 > poly caps in many
 > >of his magnifier coils which I have seen in a few of his videos.
 > >He was using these with both 14.4kV and 34.5kV potential
 > transformers.  I
 > >believe he used two of these caps in series for an equi-drive type
 > >system for use with his magnifiers.
 > >
 > >Dan
 > >
 > >
 > > > A home made cap used with a 15kV power supply must be
 > made from at least 2
 > > > or 3 individual caps, in series.  A single
 > > > cap will fail due to corona at the edges of the foil.  I
 > spend a huge
 > > > amount of effort on two attempts at rolled poly caps.
 > The first used a
 > > > single layer of 40 mil poly, and dies after a few
 > minutes.  The 2nd
 > >attempt
 > > > was made with two units in series, each with a single
 > layer of 40 mil
 > > > poly.  It too died after several minutes (see
 > > > http://www.laushaus-dot-com/tesla/rolledcap.htm).
 > > >
 > > > Assuming you are using 60 Hz power, your cap is
 > mains-resonant with the
 > > > NST, and this is a bad thing.  In addition to being
 > healthier for the cap,
 > > > I have found that a value of about 2X the mains-resonant
 > value gives the
 > > > best performance with a static gap.
 > > >
 > > > Regards, Gary Lau
 > > > MA, USA
 >
 >
 >
 >
 >