Re: Homemade Capacitors

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: tesla popp <teslas_lab@xxxxxxxxx>

Fine job Dr.bill!  Polypropylene is a very good
material to use.   From the sound of it, you have an
excelent capacitor.  The fact that no oil is needed
already puts it on my good ideas list.  I HATE WORKING
WITH OIL FILLED CAPS!  I would like very much to see a
few pictures of this cap when you get a chance.

Even an mmc guy like me can see quality in this
design,  wish I would have seen this before I started
ranting about homemade caps.

Coiler Forever: Jeremiah Popp



--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Drbillpmt@xxxxxxx
>
> Hi All,
>
> I've been following the capacitor emails for some
> time. Maybe my
> capacitor making method will be of some help.
>
> First:  I use polypropylene as a dialectric. The
> source for it is the
> film used to tint vehicle windows. Not all of it is
> polypropylene,
> but much of it is. Some of it is as thick as .025 or
> even more. At
> 650 VDC per Mil, .024 would give you 15,600 VDC.
>
> Second: I use brass shim stock for the metal. It is
> .005 thick and
> rolls quite easily. It is 2-Inches wide. Using
> 4-Inch strips of the
> poly, I leave one inch on both sides of the metal.
> For connections, I
> turn the shim stock 90 degrees and flatten it so I
> have a 2 inch
> strip coming out of each end of the roll. It is not
> easy to roll but
> it can be done.
>
> Third: After the cap is rolled, I place tie-wraps
> around the assembly
> to hold it together. My first try was for a cap that
> needed to be
> around 0.004 UF for a 5 KVRMS output transformer
> with the spark gap
> across the transformer secondary. The capacitor went
> from one end of
> the spark gap, through a 20 Ohm non-inductive 75
> Watt resistor to a
> spiral coil center. From the end of the spiral, I
> connected to the
> other side of the spark gap.
>
> This setup now has over 20 hours on it with no
> problems. The cap
> stays cool. And the cap is dry - NO OIL!
>
> I see no reson why one could not make a higher
> capacitance unit, for
> a higher voltage the same way, just scaled up.
>
> Dr. Bill
>
>
>