Re: simple question about ballast cores

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

Original poster: "Metlicka Marc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>



> Hi Justin....
> 
> what you are contemplating is more frustrating than all the other items you
> mentioned
> in your post. True you will have a non saturating "inductor" with the
> design in mind
> but you should take into consideration that the thickness of the wire
> needed for this
> will be a # 8 or smaller for 10KVA application.
> 
> When it comes to inductors, you have to take into consideration the amount of
> amperage flowing thru the inductor. Even tho a #10 can handle 30- 38 amps (
> depending
> upon insulation qualities), this is considering the cooling factor allowed.
> Most
> applications of a # 10 wire carrying 25+ amps is considered in an open air
> enviroment, not coiled upon itself ( where the heat generated from the
> inner coils
> cant get out and thus melts the insulation and shorting occurs)
> 
>


on the large input reactors for ac drives that i have, the flat ribbon
wire windings are spaced apart with phenolic blocks at about every six
layers. this i'm sure is for cooling by allowing air to travel up
through the windings by convection. if you wound yours the same way, i
would think heating could be held to a minimum? try using a thhn or a
xhhn wire and this could run upwards of 200 deg.f.
i think the wire strand core would work for you, maybe a pipe for the
wire core fitting into a pipe for the bobbin would give you a sliding
core that could be moved for the current set? make the wire core "BIG"
for the proposed 100 amp limit though.
marc