Re: ballast bobbin...again

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

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

i have an inductor from a 75 hp ac drive that is wound from flat wire
and uses spacers to hold each layer away from the others it is wound in
an oval over the square core. i thought this might be for cooling? i
will be sending jim a pic for his "hv components" data base of things to
look for. 
marc m.

Tesla list wrote:
> 
> Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<pkomen-at-zianet-dot-com>
> 
> FWIW: I have an isolation transformer (1kva, 120v to 120v) in which the
> secondary is about 3/4 to 1 inch away from the core.  It has cardboard
> spacers to keep the clearance.  It works fine.
> 
> Regards,
> 
> Pete
> 
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Tuesday, May 01, 2001 11:34 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: ballast bobbin...again
> 
> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <jimlux-at-earthlink-dot-net>
> 
> This would work fairly well.  Very large transformers (1 MVA and up) use
> laminations that are of different sizes so that they can approximate a
> circular cross section. Transformers where cost is important use square or
> rectangular cross sections because it is cheaper (they make those E and I
> sections by the millions)
> 
> I doubt that the leakage reactance increase from spacing the windings away
> from the core would be all that significant, assuming that you don't have
> an air gap in the core.  HV isolation transformers are often made with the
> HV winding as a separate "donut" that is slipped over the core laminations.
> 
> Tesla list wrote:
> >
> > Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> <CTCDW-at-aol-dot-com>
> >
> > Hey all!
> >
> > I have a quick question. In my search for a suitable bobbin material, I am
> > wondering how close the wire need to be from the core. I assume that right
> on
> > the core is the best, but can I wind on PVC pipe and put the core inside?
> It
> > is a straight core. I could actually get some more steel and completely
> pack
> > the pvc inside so it would be a more or less round cross section.. any
> help
> > would be appreciated! :)
> >
> > THanks!
> >
> > Chris W