RE: [TCML] Interesting Coil Wrap

[Jeff Behary <electrotherapy@xxxxxxxxxxx>]

Speaking of this, and why some systems had two primary coils in general, the hardest part about making a bipolar coil is holding the secondary coils in place by something that won't eventually start conducting.  Even acrylic or polycarbonate can start arc tracks if the current is high.  By having a firm vertical center piece, you can easily mount 2 secondary coils (wound in the same direction, or a large coil cut in half) and then ground them in the middle.  The only inconvenience is that by having a vertical piece it often conflicts with the primary coil - making two primaries sometimes neccessary.
 
In that one coil I did, I made a wooden box with cutouts for the secondary near the low voltage ends of it.  I put the primary inside and filled it with wax to avoid any problems.  In this case it was a continuous secondary coil.  It might have been easier though to have one piece of wood firmly mounted, a flat primary coil on both sides, and two secondaries firmly mounted to it as a base.  The two primaries could always be joined in parallel through the wood...
 
Just ideas...
Jeff> From: youngs@xxxxxxxxx> To: tesla@xxxxxxxxxx> Subject: RE: [TCML] Interesting Coil Wrap> Date: Sun, 3 Aug 2008 20:52:15 -0600> CC: > > Jim, you are correct regarding the secondary winding. If you can GUARANTEE> the only streamers will be between one end of the secondary and the other> end, then you don't need a mid-point ground. HOWEVER, if a streamer jumps> from one secondary end to ground, then the other end of the secondary most> likely will arc to the primary, unless the secondary midpoint is RF> grounded. Best to ground the midpoint.> > --Steve Y.> > -----Original Message-----> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf> Of Jim Mora> Sent: Sunday, August 03, 2008 6:52 PM> To: 'Tesla Coil Mailing List'> Subject: RE: [TCML] Interesting Coil Wrap> > Hi Jeff,> > Was this a misprint? I thought a bipolar (1/2 wave) coil is usually wound in> the same direction to 2x the usual 3.5-5:1 ratio. A space may be provided at> the mid point to control the coupling. The advantage of this configuration,> if I am not mistaken, is that no RF ground is needed at the midpoint. Please> correct me if I am off on this as I want to build one of these. And I have> read several conflicting responses over the last couple of months.> > Thanks,> Jim Mora> > > _______________________________________________> Tesla mailing list> Tesla@xxxxxxxxxxxxxx> http://www.pupman.com/mailman/listinfo/tesla
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