Re: T-24 Hours Until New (Really Bright 10KVA) Light...

["Barton B. Anderson" <tesla123-at-pacbell-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Ryan, 

Tesla list wrote: 
>
> Original poster: "Ryan Ries" <spud-at-wf-dot-net> 
>
>         Why is 8 ohms too much?  Is not as simple as 240v / 8ohms = 30A?  Or
> is it 
> just because of the extreme heat/power loss? 
>
>         Ryan Ries 
>  

The resistive current limiting is only part of the picture. Inductive reactance
must be accounted for as well. The xfmr, ballast, resistor, and wiring are all
in series and parallel to the AC source. 

Bart 
>
>   
> ---------- 
> > From: Tesla list <tesla-at-pupman-dot-com> 
> > To: tesla-at-pupman-dot-com 
> > Subject: Re: T-24 Hours Until New (Really Bright 10KVA) Light... 
> > Date: Thursday, September 14, 2000 12:53 PM 
> > 
> > Original poster: Esondrmn-at-aol-dot-com 
> > 
> > In a message dated 9/12/00 9:47:02 PM Pacific Daylight Time, 
> tesla-at-pupman-dot-com 
> > writes: 
> > 
> > << 
> >     My 10KVA pig has been sitting very patiently in the garage awaiting 
> its 
> >  moment of glory.  We have almost finished wiring up the big extension 
> cord 
> >  that is to be run from the big 240v dryer outlet.  Very convenient since 
> >  that is only about 10 feet from where the transformer will be.  We have 
> a 
> >  great arc welder to work with for ballasting, but I also went to the 
> local 
> >  junkyard and ripped an element from a dryer.  With my DMM, it measures 
> >  about 8 ohms.  Does that sound right?  I hope so, because I like the 
> idea 
> >  of my coil running at a cool 30 amps. :-)  Also, I imagine that that 
> >  element is bound to get VERY hot.  What do ya'll suggest to keep it 
> cool? 
> >   >> 
> > Ryan, 
> > 
> > 8 ohms of resistance in series with the inductive ballast is a bit too 
> much. 
> > You want somewhere in the range of .5 to 2.5 ohms.  I used to use an 
> array of 
> > about 7 oven elements wired so I could switch in only one or all 7 of 
> them in 
> > parallel.  I now use fixed resistors.  I use a large fan blowing on the 
> > resistors to help get rid of some of the heat - and yes, they do get real 
> hot. 
> > 
> > Ed Sonderman 
> > 
> > 
> >