Re: Arc Welders as Rheostats?? Variac Mod Question

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

Original poster: "david baehr by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dfb25-at-hotmail-dot-com>


Is there any way of you getting a welder or making your own inductor?? It
would be a shame to cut a good variac! 

>From: "Tesla list" 
>To: tesla-at-pupman-dot-com 
>Subject: Re: Arc Welders as Rheostats?? Variac Mod Question 
>Date: Fri, 29 Mar 2002 10:49:40 -0700 
> 
>Original poster: "Ed Phillips by way of Terry Fritz " 
> 
>Tesla list wrote: 
> > 
> > Original poster: "Jack King by way of Terry Fritz " 
> 
> > 
> > Anyone out there have data on how "wide" the air gap 
> > needs to be? My gut says something like .75-1" should 
> > be sufficient to interrupt the flux travel...any 
> > thoughts? I'm toying with "modifying" a 7.8 kva unit 
> > for use as a series reactive ballast, and would like 
> > additional insight before i dig out the band saw. 
> > Also, does one need to replace the removed section 
> > with epoxy or something along those lines to maintain 
> > structural integrity? Lastly, might anyone know off 
> > hand if cores on these older, larger dogs are silicon 
> > steel strip or scintered iron encapsulated in epoxy? 
> > 
> > Cheers, 
> > 
> > Jack King 
> 
> That sounds like way too much gap, but I'm not an expert on calculating 
>magnetic circuits. Someone else here probably is and can give you an 
>answer. I would suspect the actual value should be of the order of 
>0.050", depending on the core area and the number of turns. 
> 
> Don't think any 60 Hz transformers use anything but silicon steel for 
>the cores, with the exception of very recent ones which use some of the 
>"matallic glasses" for ultra-low loss cores. 
> 
>Ed 
> 
> 
>