Turn on Surge Re: Non ballasting a pig?

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

> Why would it appear as a short unless you short the

> output windings?

	Because that is the way transfromers act/work.

	That 'secondary (output/load) impedance is reflected

	back to input is PART of the story.  For 'normal'
	(say under 100W) transformers the effects, and
	currents surges, are small enough not to be noticed.
	Above that, turn on surges start becoming noticable,
	have been discussed here, at length.
	Short version:
	There Will Be a turn on surge, roughly 10x normal
	full load current.  This will peak at the first cycle,
	and drop off afterwards.  This is independent of
	secondary/output load.  The EXACT magnitude depends
	on detail transformer design and exactly when, in
	the line cycle, the switch is closed.

	Physics, informal:
	It takes a certain amount of time, brief, by human
	standards for mag fields to 'penetrate' the steel
	in the core.  Until THAT happens, the core looks like
	'air', which means the only thing limiting current
	flow is the DC RESISTANCE of the transformer winding.
	This results in a high surge.


> The coil I'm working on will be DC powered so I don't have to play

> the impedance matching and current limiting game with my polemount

> transformer.

	Still advisable to limit input current, or get a surprise.


> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Monday, October 14, 2002 9:32 PM
> Subject: Re: Non ballasting a pig?

>>Original poster: "Barton B. Anderson by way of Terry Fritz
>><twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
>>Hi Gregg,
>>You "must" ballast the pig regardless. Connecting the pig

>>without a ballast will appear as a short circuit. These

>> transformers will pull many times their rated amps in

>>short circuit conditions.

...

	best
	dwp

...the net of a million lies...
	Vernor Vinge
There are Many Web Sites which Say Many Things.
	-me