Re: Secondary catastrophe

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

Original poster: "Harold Weiss" <hweiss-at-new.rr-dot-com> 

Hi Andy,

It's best to coat a new coil as soon as it is done being wound.  I have had
this problem to a much more limited extent.  Part of it is too much slack in
the windings and part seems to be streching of the wire.  I have found that
even the tighest wound secondary will loosen enough to pop a winding if left
overnight in a vertical position.  I would keep working at it till the coils
are back in place.  Starting at the top, try to turn the wire in a
tightening direction while pushing the wire upwards.  You should start
getting a gap forming as you work your way down.  You will get a few more
popped turns on the way down.  Just keep working the gap/popped turns down
and it should work itself out.  At the bottom, you will, more than likely,
have to reterminate to deal with all the slack.  It's a long slow process
but it can be done.

If you really want a headache, try doing a coil with 14 ga that had been
spooled with too much tension, which gave the wire small kinks.  After a
week of trying to flatten it all out, I finally gave up and coated the coil.

David E Weiss

 > Original poster: "andy g" <aggniu-at-hotmail-dot-com>
 >
 > Hello again,
 >
 > I may be asking a question that has already been answered and that I think
 > I might already know the question to, but I will fire away anyhow.  I am
 > still in the process of building my first coil, and the other night I
 > started working on the secondary coil.  I am using a piece of 4"(nominal)
 > 4.5"(O.D.) PVC for the form (I know it is quite lossy, but I am a poor
 > college student) wound with 22AWG magnet wire.  At any rate, I finally got
 > the thing done and was going to coat it with poly the next morning as I
 > didn't have any on hand, and I came to find after letting it sit for a
 > while I had spots where the wire wasn't completely flat on the form (kind
 > bunched up where there wasn't enough space between windings/there was too
 > much wire and nowhere for it to go).  So, you can all see where this is
 > going, I ended up getting a mess of doubled over windings and a hell of a
 > headache at about 1:00AM.  By the time I went to sleep, the gosh darn
thing
 > looked like a backlashed fishing reel.  The good news is that I saved all
 > but the last 4" of windings.  My question is, should I take the time to
try
 > to do a splice (rewinding is out of the question, I don't have enough wire
 > to redo the entire thing)? Or, should I cut my losses and settle for a
 > shorter than expected secondary?  If I do use a shorter secondary, what
 > sort of performance change could I expect?  Originally, it was going to be
 > 21" of windings.  Now, it is a shade over 17" of good windings.  If it
 > would be possible to splice, what is the appropriate way to approach such
a
 > thing to make it perform optimally?  For what it is worth, at this point I
 > am locked into using a 12KV 30mA NST for power, otherwise, no values are
 > definite.
 >
 > _
 >
 >
 >