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Re: Rolled PE Caps
I have to disagree with you here Reinhard. At least from my experience,
The heavy duty foil works very well without corona flashover. I didn't
round off the corners. The creasing can be kept to a minimum by having a
helper hold the bottom layer of poly as the cap is being rolled, and I
did use aluminum strapping for my terminals.
Yes, they are a bit fragile, so you have to handle carefully. But by
cutting a length 36" long (heavy duty Reynolds wrap), folding that in
half (18" now), then folding it over and over on itself in about 3/4" -
1" wide laps, you come up with an easy to make terminal. I only
connected with a couple pieces of tape before I rolled cap, the pressure
of the tight roll, plastic ties, and the swelling of poly in oil has
created a nice cap with no problems to date. The holes for the terminals
can be made with a punch or sharp drill bit.
This is an inexpensive and easy to make solution for beginning coilers
on a tight budget.
It doesn't compare to yours or Gary's beautiful MMC's, but it's a great
way to get started. I think I had about $50-$60 total investment for
three caps at .033uF each, wired in series.
Sparkin'
Bob Volk
> >Disadvantages in using AL foil instead of flashing:
> >--------------------------------------------------------------
> >1.) It creases very easily: > trapped air >partial discharges >cap death
> >
> >2.) You canīt use the foil as a connector. It is way too fragile. This
> > means you need some solid way to connect the plate to the
> > connection terminal (like using straps and screws to attach
> > the connector to the actual cap plate.
> >
> >3.) Foil is ultra thin. It is nearly impossible to "round" the cut
> > edges. This, too can encourage corona production.