Re: Inductor Interference

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <FutureT-at-aol-dot-com>

Sam,

What size NST are you using?  That determines the max LTR size.
What wire size were you using originally before the 28 gauge?

You can arrange the extra inductance coil vertically so the fields
will tend not to interfere if you'd like.  If you place the extra inductance
under the primary wound in the same direction, the inductances may
increase more than expected which would be a good thing, since you'd
need to add less.  This depends on the size and closeness of the coils.

John,

>  
>   Hey all,
>  
>   I thought I'd try to redo my 3 inch coil to optimize performance,
>  I'm getting 12 inch arcs now.  I'm rewinding the secondary, 3X12 inches,
>  with 28 Ga wire.  The spark gap is getting changed from a two-gap RQ to a
>  more-than-two-gap SD.  The primary is being rewound on a 30-degree inverse
>  conical form.  There is one problem, the resonant frequency of the
>  secondary is lower than the space allows for tapping out.  So there are two
>  solutions:
>   One-Increase the value of the capacitor.  I don't what the maximum
>  amount is for LTR, but if anyone has it, I'd appreciate it.
>   Two-Add some extra inductance.  This is what I've been doing so
>  far.  The only problem I see is that if I mount the helical extra inductor
>  onto the base, directly under the primary coil(and with only 1/2 inch of
>  HDPE separating them) with their axes parallel, there could be some kind of
>  destructive or degrading interference as their magnetic fields interact.
>  Comments anyone?
>  
>   Sam Beck
>