Re: Elevating Secondaries (was Re: First Spark)

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

Original poster: "David Speck" <dave-at-davidspeckmd-dot-org> 

Matt,
There are numerous examples of electrically driven linear actuators on eBay 
and at various suppliers.  These devices are not very fast, but can exert 
100's of pounds of force.  You will have to make a non-conductive extension 
to get the metallic parts down below and  out of the way of the majority of 
the field of the primary.  Making useable threads in non-conductive plastic 
materials is not an easy thing to do.
You can get inexpensive 3/8" x 48" round white fiberglass electric fence 
posts at a farm store for less that $1.00 each.  A circular array of 6 or 8 
pieces, held rigid by periodic plywood discs would allow you to adjust your 
secondary during operation.  A couple of list members have used a similar 
arrangement to adjust the cores of ballast inductors during 
operation.  Perhaps a bit of overkill, but very slick.
I think MPJA-dot-com had them a while back, and also possibly SCIplus-dot-com.
Just don't bid me up on the one I'm trying for on eBay right now!  ;o)

HTH,
Dave


>     In keeping with your suggestion, I am looking for a low-rpm motorized 
> jack screw with a large (~1") diam. non-conductive screw, nut, and base 
> plate. Here in the hills of WV, there is a plastics fabricator where I 
> can have one made, but they want my "left one" as a down payment. 
> :^(((  Anyone have a line on a surplus place that might handle an item 
> like this?
>
>Matt D.
>