Re: secondary wire diameter

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dmitry (father dest)" <dest@xxxxxxxxxxx>

Hello Malcolm aka "all" :-D

> Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

> Hi Dmitry,
> On 14 Aug 2005, at 12:44, Tesla list wrote:

>  > Original poster: "Dmitry (father dest)" <dest@xxxxxxxxxxx>
>  > hello all.
>  > how do you choose secondary wire diameter?

> I've found performance for
> Q's below 100 to be questionable and one coil I wound which had a Q
> of 40 to be worth little more than scrap copper.

it`s strange - as i wrote before, while working in 3:4 mode losses
shouldn`t be too high - you may have been working at 9:10 or
something, or even at 11:12, that is coupling coefficient of that coil
was about 0.105-0.087.
i hope several polyethylene layers would allow me to have k=0.28, so i
could decrease wire diameter 2 times more, but winding 3000 turns -
nooo, thanks :-)

>  > imagine we have a certain secondary coil form, coil winding lenght -
>  > 1m. it`s known - "the more inductance - the better" - ok, but at very
>  > high number of turns the Q of the coil is decreasing. what minimum Q
>  > value could we use on practice?

> There is an optimum for a given coilform. Quantifying that optimum
> exactly is not something I think has been done to date. The thing
> about high inductance has more to do with reducing primary losses
> than secondary ones. Primary losses are always higher in my
> experience.

that`s true - secondary inductance is needed only for increasing
primary inductance, to decrease influence of sg losses. and as sg are
different, or the same coil is used with different types of sg - there
might not exist a unified optimum - or there`re some of them - each
for its sg type?

>  > how does the power of the coil is connected with the wire diameter -
>  > for example, what wire should we use at 2-4kw?

> I just choose the coil length for some maximum output voltage, go for
> an h/d ratio in the 3 - 5 region and wind either for high inductance
> and moderate Q or more moderate inductance and higher Q.

nobody wants to wind 10000 turns, so actually there`re probably no
big difference what wire size to use - if sg quenches bad, energy is
dissipated in the primary, if it acts good - energy would go for
corona and rf emission, right? :-)
but situation becomes interesting if one wants to get maximum from
given secondary, ex. - having increased primary power until flashovers
levels, we still can increase the power further - increasing bps for
example, or to put a bigger toroid - what would happen then?
at all - don`t you think that coils projected for sparks of 3..4 (and
more) secondary lenghts just can`t have low bps - just for the
voltage decreasing, coz the toroid with radius more than secondary
height is not looks so pretty, right? i have the same problem now  -
my toroid with 1.2m diameter looks ugly and it`s at 900kv at 100bps :-(

>  >  LDPE - could i make the coil from it?

> If it's not black, it should be fine.

i saw different colours - blue, white, yellow, why black is so bad -
it contains graphite?

> Malcolm

* If it's under 10Amps it's leakage current *
:-D