RE: Pig Question AND current limiting method

["Oxandale, Terry" <Toxandale-at-SPP-dot-org> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Once, and only once, I used the solenoid slug (piston, rod, whatever you
wish to call it) as the core for a very large reactor (originally is was
a solenoid coil used to close 13.8kv distribution breakers). It became
too hot to even touch in less than 30 seconds of run time. This core was
solid iron 3" in diameter and 6" long. It was very effective in limiting
the current (DC was originally used in the coil), but totally
impractical. To reduce the eddy current heating, I replaced the core
with about 200 1/8" welding rods all bundled together and then inserted
into the coil. This never gets hot (the flux is non-conductive for this
purpose) because of the many pieces of insulated rod instead of the one
large core, and the resulting current is at very useable levels.
Whenever I want to increase the current, I just space the core up a
little bit further out of the coil (reactor).

Terry
> ----------
> From: 	Tesla list[SMTP:tesla-at-pupman-dot-com]
> Sent: 	Friday, August 04, 2000 7:42 PM
> To: 	tesla-at-pupman-dot-com
> Subject: 	Re: Pig Question AND current limiting method
> 
> Original poster: Tesla729-at-cs-dot-com 
> 
> In a message dated 8/4/00 11:09:46 AM Pacific Daylight Time,
> tesla-at-pupman-dot-com 
> writes:
> 
> << i was wondering if anyone has tried a window sash weight for the
> core? >>
> 
> Marc, all,
> 
> I'm certainly no expert on xfmr/inductor design, but it seems to me
> that these
> things would be a nightmare for eddy current problems and get very hot
> since
> thet are one solid piece of steel. I wouldn't imagine cast iron would
> have 
> very
> good magnetic permeability properties either (low guass saturation?)
> Does 
> any better qualified individual(s) out there have any insight on this
> matter?
> 
> Good, Safe Coilin,
> David R.
> 
> 
>