[TCML] Wire gauge for large diameter secondary?

[Kurt Schraner]

Hi Conor,

the secondary of my B&W ~16" coil is spacewound 820 turns with 
double-coated
1 mm2 Thermex 2.5 (enamelled) wire (diameter 1.33mm, with insulation).
As a distance-keeper we wound a ~0.9mm cotton thread. The spacewinding
proofed useful, not so much for saving copper, but when some primary to
secondary arcs hit the sec, and needed small polyurethane repairs. For
more details click on:

http://home.datacomm.ch/k.schraner/b_and_w.htm
http://home.datacomm.ch/k.schraner/bw_sec.htm

If doing the job again, I might use PVC-coated wire, which is thick
enough (with insulation) to result in the right H/D ratio of ~4.5-5,
when using closewound practice.

Best regards

Kurt

ConorPerry at comcast.net wrote:
> I'm trying to help someone with a 20" secondary which is starting to
> fall apart.  It's space wound, probably 20-22 gauge wire, and the
> windings are seperating from the PVC.  This has caused several
> locations of arcing between windings and carbon tracking.  All the
> modern coils that I've seen (12" and under) are tightly wound using
> the wire gauge size which will cause the correct winding lengths. But 
> when you get into a secondary this large what to do?  Is THHN,
> TFFN, or MTW suitable at all?  Is space-wound still and option to
> help save on copper costs?  If we do space-wound, what gauge should
> be used?
> Conor
>
> _______________________________________________
> Tesla mailing list
> Tesla at pupman.com
> http://www.pupman.com/mailman/listinfo/tesla