Re: Flat spiral or helical primary?

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ralph,

The first problem a solenoid primary will have is primary to secondary
arcing.  Get lots of plastic sheeting for insulation.  The second is that
the coupling may be too high.  However, you can move the primary and
secondary apart to control that.

Cone primaries give a little higher coupling which may be good or bad
depending on exactly how the coil is made.  Some people like the way the
inverted cone primaries look too.

Flat primaries usually give perfectly fine coupling and are easy to make.

Cheers,

	Terry

At 10:41 AM 3/1/2002 -0500, you wrote:
>Can someone please 'splain me the relative merits
>of a primary wound as a flat Archimedes spiral and
>a primary wound as a helical solenoid?
>
>I have seen a few coils use a solenoid primary. A few 
>wound with strap, but it seems that these are usually
>large coils. The flat, Archimedes spiral is almost
>always used by coilers. Why?
>
>I am in the process now of converting one of my 
>24 inch secondaries from the twin bipolar into a 
>1/4 wave coil. I have many solenoids of various
>configurations that I will at least try with the
>1/4 wave TC before making a flat coil. 
>
>Happy day,
>Ralph Zekelman
>
>
>