RE: any insulation recomendations for magnet wire

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi John,
         I'm not sure that V/turn is a particularly useful 
concept when it comes to rating resonator insulation. An 
example: I can test a certain gauge of wire (with a 
correspondingly thick coating of polyesterimide or whatever) 
to 6kV without it breaking down between two adjacent pieces of 
the same wire. More actually - I'm being conservative. So, 
let's say we have a coil actually doing 6kV/turn and 
furthermore that coil has the "standard" 1000 turns. I can 
wind something like that with a height of less than a metre. 
But can I get output to hit the insulation limit of my wire? 
Not a show in hell - we're talking about 6MV over a distance 
of less than 1m. Cannot be done without winding flashovers. 
Generally one finds that the tracking distance required to 
prevent a flashover does not adhere linearly to the total 
voltage.
      I bet there are very few if any coils which even come 
close to taxing the turn-turn wire insulation. I think your 
program should instead be looking at total voltage/total 
secondary length.

Regards,
Malcolm
 

On 17 Jul 00, at 18:25, Tesla list wrote:

> Original poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net> 
> 
> 
> Ed, David -
> 
> As you know I am interested in the design of Tesla coils and improving my
> JHCTES Ver 2.3 TC computer program. Therefore, when somone mentions TC
> design my interest is aroused because I may learn something new. Tesla
> coilers have always had the problem of the secondary wire insulation
> breaking down during coil operation. As you said this could be due to faulty
> design. However, it could also be due to a well designed coil except for not
> enough secondary wire insulation. How would the designer know this without
> information regarding the voltage stress on the secondary wiring?
> 
> When I was developing the JHCTES program I realized a parameter that would
> alert the designer to the secondary wire voltage stress would be of use in
> the selection of the wire insulation. The parameter I choose was a "volts
> per turn" which varies with every coil. It is obvious this parameter is
> approximate but does give the designer guidelines with which to select the
> secondary wire insulation.
> 
> Ever coiler who has done much coiling has at one time had problems with
> secondary wire insulation breakdowns during operation. These breakdowns can
> occur anywhere along the secondary coil. The voltage to ground varies
> nonuniformly from the bottom to the top terminal of the coil. However, the
> volts per turn would vary very little so an approximate average volts per
> turn can be used. At present the estimated volts per turn can be found only
> in the JHCTES Ver 2.3 program.
> 
> John Couture
> 
> ----------------------------
> 
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Sunday, July 16, 2000 5:01 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: any insulation recomendations for magnet wire
> 
> 
> Original poster: "Edward Wingate" <ewing7-at-rochester.rr-dot-com>
> 
> Tesla list wrote:
> >
> > Original poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
> >
> > David -
> >
> > "if the system is designed properly". What are the proper design
> > requirements for using the single vesus the double insulation? The JHCTES
> > Ver 2.3 program gives a "volts per turn" parameter for making this
> decision.
> > What are your ideas?
> >
> > John Couture
> 
> John,
> 
> You still haven't read pages A-22 and A-23 in Richard Hull's book that I
> referenced you to some time ago, have you?
> 
> What David is trying to say is that it just doesn't matter whether you
> use "single or double" insulation if the coil is designed, built and
> tuned properly! If someone wants to opt for extra insulation on their
> secondary wire for a little (very little) extra insurance against
> arcover during the tuneup process, great, oterwise it just doesn't
> matter!
> 
> How can you have a volts per turn parameter in your program when in
> reality the turn to turn voltage in a real live secondary or extracoil
> isn't uniform from bottom to top?
> 
> Ed Wingate RATCB
> 
> 
> 
> 
> 
> 
>