Re: Secondary Construction
Subject: Re: Secondary Construction
From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Date: Tue, 3 Oct 1995 11:57:02 +1200
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With reference to this....
> Date sent: Mon, 2 Oct 1995 09:00:07 +0700
RQ> Quoting Steve_Crawshaw_at_erith6-at-smtpgwy.supertension-dot-com:
> > I have asked this before, but I can't remember if I got an
> > answer. When constructing the secondary coil, I seem to recall
> > that RQ recommends sealing end caps on the former. Why is this?
RQ> In a high performance design, properly driven, the secondary coil
RQ> is easily capable of producing sparks that greatly exceed the
RQ> physical height of the secondary coil. In other words, your coil
RQ> may be 20 inches tall producing sparks that are 30 inches long.
RQ> Under these conditions an "open" or uncapped coil will almost
RQ> certainly fail. All of the electrical failures that I have seen
RQ> occurred inside of the coil form. The failures resulted in
RQ> sidewall perforations, arc scoring, and carbonization of the coil
RQ> form. I have never been able to successfully repair a coil once
RQ> it has failed in this manner.
Point taken, but...
Can anyone explain why sparks would prefer to travel down the inside
of the former (winding) rather than the outside ?