Re: Pig Question AND current limiting method

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

On 2 Aug 00, at 18:30, Tesla list wrote:

> Original poster: LTM-at-SUBSONIC-dot-com 
> 
> Your question   "And what is the 'up-to-date' current limiting method? arc
> welders and 
> resistive ballast (oven elements)?"  
>    I used rebar tie wire (could use baling wire also) pulled it taught for
> straight pieces, cut it to the desired length, also cut a piece slightly over
> twice the others length to bend in half to fashion a loop for pulling
purpose,
> and coated them with varnish. Note: Each piece is individually coated. After
> adequate drying time, placed all coated rods in a PVC pipe for tight bundling
> and forced all rods out at the same time so they could be taped as a bundle.
> One could also keep these rods in a non metallic pipe and fill with resin. 
>    I wound a 8 Awg bare copper wire around the full length of the bundle
making
> sure it wasn't too tight, enough for the core bundle to freely slide
within the
> coil. I coated the coil with  polyester resin AKA fiberglass resin for a
tough
> surface. 
>    The way this works, when the core is in the coil, the core saturates and
> limits the current. Pull the core slowly out of the coil, and the current
> rises. 

I hate to be pedantic but if the core saturated, the coil 
would assume the inductance it would have if the core wasn't 
present at all.

Malcolm

>    It was easy to locate the supplies, and rewarding to make. Also it's
> infinitely variable.
> Hope this helps for part of your questions.
>    
>       Shawn T. Ferrell
>             COIL ON
> 
> 
> 
> At 10:01 PM 08/01/2000 -0600, you wrote:
> >
> > Original poster: "Dan Kunkel" <dankunkel-at-hotmail-dot-com> 
> >
> > Coilers,
> >
> > I went to the power company today to see if I could procure for myself a 
> > pole pig. The company only runs 7,620 volt lines and there 10 kva-ish 
> > transformers are all single bushing. I was wondering if anyone esle has
had 
> > experience with these kind of transformers. They are upgrading their load 
> > capabilities are getting rid of the smaller trannies at scrap cost 
> > (awesome).
> >
> > I was wondering if it is possible/nessecary to buy two trannies and wire 
> > them in series to produce 15,240 volts in order to reduce amperage and
still 
> > keep the wattage the same. I would want to reduce the amperage so i don't 
> > have nightmarish spark gap quench problems.
> >
> > Also when wiring the these transformers in series, do you just connect the 
> > ground (the case) together and draw the HV off each bushing?
> >
> > And what is the 'up-to-date' current limiting method? arc welders and 
> > resistive ballast (oven elements)?
> >
> > thanks
> >
> > Dan
> > ________________________________________________________________________
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> 
> 
> 
>