Re: Ballast inductor

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

Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sundog-at-timeship-dot-net>

Hi Ed, All
         Without being a specialist on this, it's been my experience with 
home-brew ballasts that you need at least 150 turns or so on it before you 
begin seeing any significant current-limiting.  28 turns isn't a whole lot, 
especially compared to what came off of it.  Maybe you can try using heavy 
magnet wire on the core instead?  I forget how many turns are on my present 
pig ballast, but I believe it's ~240-260 mark.   The ballast itself is big, 
about 80 lbs or so, and handles 240v30A for a good 10 minutes without any 
trouble or significant heating. Keep trying, and let us know how it works! :)
Shad


At 11:50 AM 2/25/02 -0700, you wrote:
>Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><Esondrmn-at-aol-dot-com>
>
>I wound a new ballast inductor last night using the previously mentioned 7.5
>amp variac core that has a 1/4" slice cut out of it.  I managed to get about
>28 turns of #8 wire on this core.  My previous ballast, using a 5,000 watt
>variac, measured about 25 mh at the one half scale position where I normally
>had it set.  The new inductor measures only .40 mh.  I was surprised it was
>this low.  Is it possible that the Wavetek meter cannot supply enough current
>to magnetize the core, thus the measurements are about what I would get with
>the same number of turns wound around say a plastic form?  If this is the
>reason, why does the meter appear to measure the 5,000 watt variac properly?
>
>Maybe I should hook it up to a low voltage 60 hz source with a series
>resistor and try to calculate the inductance.
>
>Thanks, Ed Sonderman

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Shad (Sundog)
G-2 #1203
"Ever stop to think, and forget to start again?"
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