Re: induction question

["Alex Crow" <user-at-xxxxxxxxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Scot,

What's the ratio of this transformer? It sounds like the load being 
effectively presented is largely resistive (not what you want) and is 
dropping most of the supply voltage. You don't want the ballast to be 
dropping a full 240V at the desired current, which is why people tend to 
rely on limiting current with a big inductance and stabilising it against 
resonances and 'growling' with a small series resistance. You may want to use 
the trannie core with one new winding (possibly gap the core as well?) that 
limits the current by itself to a respectable value, or indeed search the 
archives for "saturable reactor" for a more versatile arrangement.

Hope you sort this out - try measuring the voltage dropped across your 
present ballast in operation and report back.


Cheers,

Alex

On Monday 27 November 2000 14:47, Tesla list wrote:
> Original poster: "Paul Benham" <Paulb-at-woodanddouglas.co.uk>
>
> I'm new to this, but is it that there are not enough volts on the
> primary of the pig to make your spark gap fire?  Or am I just stating
> the obvious?
>
> Paul.
>
> Tesla list wrote:
> > Original poster: "BunnyKiller" <bigfoo39-at-telocity-dot-com>
> >
> > Hi All...
> >
> > I had purchased a 5KVA transformer thru Ebay and planned to use it as
> > ballast for my piggie system. My idea was to hook this thing up ( primary
> > side ) in series with the pig ( like a welder ) and place various values
> > of reisitors ( hot water heater cores) on the secondary side of this
> > thing. By adding additional heater cores in paralell on the secondary
> > side of the transformer "should" cause the transformer to draw more
> > current thus increasing my
>
> current
>
> > to the pig.
> >
> > But ..... after i had connected this monster to my system, nothing
>
> happened. On
>
> > occasion I would get a single pop from the spark gap and no other action.
> > The secondary side of the transformer had 8000 watts of heater cores
> > attached to it. If my math is correct, that should draw 33 amps + core
> > current.
> >
> > I had checked the transformer in its "setup" condition on a direct
> > connection to 240 V supply and read 34 amps current draw. I am guessing
> > that the transformer is working properly.
> >
> > My other current limiter is an E core with 250 winds of #10 solid wire
> > and it is supplying 25 A of current to the pig. My question is why doesnt
> > this new transformer/resistor system fire off the coil ? Am I dealing
> > with some weird inductive phasing that is shifting my current phase too
> > far out and not
>
> seeing
>
> > any current to the pig?
> >
> > Scot D