RE: mysterious coil failure (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 28 Oct 2007 19:50:56 -0400
From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: mysterious coil failure (fwd)


Thanks guys,
     I don't think it was a shorted turn, there is no carbon on the inside
but there is a tiny black spot on the outside (I don't use end caps on my
coils, is this bad?).  I attach my RF ground by a copper strap, soldered
onto the end of the bottom turn, I think it arced from the sharp edge of
the strap to the wire above it (turn 2).  This occurred underneath of the
several layers of electrical tape coated with polyurethane insulation on
the bottom.  One other detail I forgot to mention, I set the coupling as
high as I could get it that night to make up for decreased performance
from wind and humidity, so that may have contributed.  I'll sand her down
and rewind the bottom and see if it works again, thanks guys.

Scott Bogard.

> Date: Sun, 28 Oct 2007 11:07:40 -0700
> From: tesla@xxxxxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: Re: mysterious coil failure (fwd)
> 
> 
> ---------- Forwarded message ----------
> Date: Sun, 28 Oct 2007 11:01:32 -0800
> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: mysterious coil failure (fwd)
> 
> Hi Scott,
> 
> Yes, the glowing spot is either a shorted turn or carbon track. It may 
> be a shorted turn and easy to fix if right on the bottom, and "if" it is 
> like the very bottom turn, it's probably too much power for too long a 
> period. I've had this happen on my 4" coil even with low coupling. If 
> enough power is provided, it can cause extensive heating a greatest 
> heating on the bottom of the secondary (highest current). If you were to 
> continue running it, a nice little fire will begin. If it's a shorted 
> turn, you'll have a nice black carbon ring around the entire turn. Real 
> easy to fix obviously.
> 
> Take care,
> Bart
> 
> Tesla list wrote:
> > ---------- Forwarded message ----------
> > Date: Sat, 27 Oct 2007 22:10:06 -0400
> > From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
> > To: tesla@xxxxxxxxxx
> > Subject: mysterious coil failure
> >
> >
> > Hey guys,
> >      I was running my 6-in MOT coil tonight for my little cousins, and it
> > died and I cannot figure out what is wrong.  The spark gap fires fine, I
> > did not adjust anything, it just died between runs, and won't arc except
> > to a grounded rod (it acts like it is badly out of tune, but like I said,
> > I adjusted nothing).  The only thing different I notice, is that there was
> > very high humidity, and I could see a tiny spark at the base of the
> > secondary.  It isn't arcing to anything, it is just a glowing spot, that
> > melted through the electrical tape insulation.  I'm stumped, I guess I'll
> > tear the insulation off of the bottom of the sec' coil and see if anything
> > is amiss, but I've never had a failure like this before.  The only other
> > possibility is that somehow my ballast malfunctioned, but I don't think
> > so.
> >
> > Scott Bogard.
> >
> > _________________________________________________________________
> > Help yourself to FREE treats served up daily at the Messenger Caf?. Stop by today.
> > http://www.cafemessenger.com/info/info_sweetstuff2.html?ocid=TXT_TAGLM_OctWLtagline
> >
> >
> >
> >
> >
> >   
> 
> 
> 

_________________________________________________________________
Windows Live Hotmail and Microsoft Office Outlook – together at last.  Get it now.
http://office.microsoft.com/en-us/outlook/HA102225181033.aspx?pid=CL100626971033