Re: [TCML] Matt tesla

[David Rieben <drieben@xxxxxxx>]

Overcoupling means that the inductive coupling between your primary and secondary coils is too tight. Think of a typical mains iron core transformer where the tightest inductive coupling between the adjacent coils is desired to have the most efficient transfer of electrical energy from the input to the output with a minimum in losses. However, this is not the case with the air cored resonantor design of a classic Tesla coil. The inductive coupling is already signifacantly reduced by the absence of a solid iron core, being replaced with only open air. If the secondary is dropped too low into the primary coil, then the coupling will still be greater than optimal for your coil and this will often manifest itself with those dreaded racing sparks along the surface of the secondary coil. A simple and pretty straight forward way to address this issue is to raise the secondary coil higher in respect to the plane of the primary coil. Try raising it at like
 half-inch increments until the racing sparks cease with normal operation. Lower it again until the racing sparks start again. Optimal coupling is the point at where the secondary is at its lowest elevation with respect to the primary coil plane and still runs racing spark free during operation. Most coilers determine optimal coupling emperically, but a good place to "start" would be to have the lowest winding of the secondary dead level with the plane of the primary coil's plane (assuming a flat Archemdian spiral shaped primary coil).
 
David

From: Matthew Hebb <matthewhebb@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> 
Sent: Thursday, May 16, 2013 11:12 PM
Subject: RE: [TCML] Matt tesla


torrid has breakout point but whats overcoupleing and how do i fix it?

> Date: Thu, 16 May 2013 20:16:16 -0700
> From: jimlux@xxxxxxxxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: Re: [TCML] Matt tesla
> 
> On 5/16/13 7:38 PM, Matthew Hebb wrote:
> > yes the do apperntly since thats what ive been told i need and oh so
> > its basicly the same type of capacitor that spark gap ones use well
> > thats less complicated than i expected.
> 
> 
> 
> So on another topic i have a
> > very odd thing happening when i use the system from my small spark
> > gap tesla coil to run my big coil ( just to tune it and see what i
> > can get with 9kv ) i get 2 foot sparks which is about the same as the
> > smaller coil got but here is the thing i need somone to explain to
> > me. For some reason there coming from the secondary not the torrid
> > the will come from all over the secondary arc wharever they want its
> > just crazy nothing comes from the torrid but if the torrids not there
> > nothing happens.... so what i wonder is is this caused by somthing
> > wrong with the coil or just because the system for my little coil is
> > not designed for this one?
> 
> Sparks all along the secondary, instead of from the toroid?
> 
> (note spelling.. torrid is "hot", toroid is a shape.. spell checker says 
> both are ok).
> 
> You might have what's called "racing sparks".. often from overcoupling 
> between primary and secondary, or, too big a toroid without a breakout 
> point.  The voltage gets too high, and you're getting a breakdown along 
> the secondary. If you put a breakout point on your toroid, you can start 
> a spark from the toroid earlier...
> 
> 
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
                        _______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla