RE: Ballast inductor.

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

My inductive ballast measured at 70mH which allows about 20amps to the
transformer.

Terry

> ----------
> From: 	Tesla list[SMTP:tesla-at-pupman-dot-com]
> Sent: 	Tuesday, October 03, 2000 9:12 AM
> To: 	tesla-at-pupman-dot-com
> Subject: 	Re: Ballast inductor.
> 
> Original poster: "Jim Lux" <jimlux-at-jpl.nasa.gov> 
> 
> 1.72 mH = 0.65 ohms reactance = 380 amps at 240VAC short circuit!
> 0.33 mH = 0.12 ohms 
> 
> I'd try winding a few more turns.. Inductance goes as the square of
> the
> number of turns.
> Don't forget that your 100 ft of #10 has a series RESISTANCE (not
> inductance or impedance) of about 0.1 ohms, also... (rule of thumb,
> #10 = 1
> ohm/1000 ft)
> 
> Also, saturation might be a problem.  That is, the current might be
> high
> enough to saturate the core, which will make the inductance closer to
> the
> "no core" value.
> 
> 
> ----------
> > From: Tesla list <tesla-at-pupman-dot-com>
> > To: tesla-at-pupman-dot-com
> > Subject: Ballast inductor.
> > Date: Monday, October 02, 2000 5:08 PM
> > 
> > Original poster: "M Fabs" <the_machin_shin-at-hotmail-dot-com> 
> > 
> > I just wound 100 feet of #10 romex THHN wire onto a 2" dia pvc
> conduit. 
> I 
> > also poly'ed a bunch of welding rods together to fit inside.  I am
> hoping
> to 
> > use this as a variac substitute, a variable inductor. I measured the
> 
> > inductance with the rods in the coil and with them out of the coil,
> and
> the 
> > numbers I found are 1.72millihenries with the rods fully inserted,
> and
> about 
> > 330microhenries with them not inside. (That last one might be off a
> bit,
> I 
> > was paying more attention to the full insertion number.)  60Hz
> 120Vac 
> > standard wall outlet is my power source.  I forgot the formula for
> inductive 
> > reactance.  Anybody willing to crunch the numbers for me and tell me
> what
> 
> > current range this will allow me?  Another option is to arrange a
> brush
> deal 
> > to use like a true variac.  Just looking for some idea as to how
> useful
> this 
> > will be, or what changes I ought to make. Thanks folks.
> > 
> > MPF
> >
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