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Re: the back of secondary winding



Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>


The idea is to securely hold the windings in place while at the same time help seal the coil from any molecular atmospheric moisture adhesion --- a big problem with PVC tubes as it rears it's ugly head especially with VDGRF generators which will not tolerate tracking/leakage values above 5 uA without serious performance degradation.

Molecular level moisture adhesion can become a serious problem especially at RF frequencies. Another serious problem most people ignore is the handling of wound coils. They handle them with their bare skin which contains a lot of oils rich with sodium compounds --- a very good conductor. Hand salt on any coil is really not the very best condition. Most coils will survive but some will fail.

Don't wind a sec coil dripping wet with varnish. Allow the two coats to throughly dry prior to winding.

Dr. Resonance



While anecdotal accounts vary, I'm not sure it's ever been demonstrated
that a coated coil will be insulation-wise more robust than a bare coil.
In a close-wound coil, since the space between turns is zero, you can't
gain anything beyond the enamel insulation.  Mostly the coating serves
to keep the wire turns from shifting on the form, and it looks nice and
probably offers some degree of abrasion resistance.

Trying to wind a secondary dripping-wet with varnish sounds like a
ticket to mess and frustration!

Regards, Gary Lau
MA, USA



> Original poster: Russell L Thornton <Russell.L.Thornton@xxxxxxxx>
>
>
> Would someone kindly explain to me the process and purpose of
> varnishing the windings of the secondary?  Specifically, it seems to
> me that when we are varnishing the coil form raw and letting that
> cure and then varnish again after we wind the wire then the back of
> the wire still remains vulnerable with just the enamel insulation of
> the wire.  Of course this assumes close spaced winding.  Or am I just
> not seeing the purpose of this exercise.  If we were doing this for
> insulation purposes I would like to put a layer of varnish on the
> form mounted to the winding mechanism and while still wet wind the
> wire.  What's up here?
>
> Russ,
> Monitoring Lightning at the Cape
>