Re: transformer theory q

["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>

[belatedly....]

Tesla list wrote:

> Original poster: "Ed Phillips by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

> >         Agree on Steinmetz.  As i recall, his methods were much
> >         more user friendly than Tesla's.
> >
> >         Tesla Transformers AT THE TIME (say ca 1890) meant what we
> >         now call an AC power transformer.  I've not got a specific
> >         cite (wish i did....)  Tesla's name (reportedly) was on
> >         the name plates, along with Westinghouse Corp.
 
> 1. Transformers have been around since the days of Joseph Henry.  AC
> power transformers, even ones with laminated cores, were around well
> before Tesla's debut.

	Around, yes.  However a lot of optimization & understanding
	was still going on.  (eg people had been heating bits of
	wire, electrically, in air and vacuum for decades before
	Edison got one that was commercially acceptable.)  I retain the
	impression that Tesla contributed to the optimization.  Consider
	that an induction motor IS an AC Power Transformer, and one that
	must be optimized, else the motor is inefficient.

	But.  Having said that, I have also checked 'Researches &
	Writings' & find minimal reference to transformers.  Westinghouse
	et al clearly improved the transformer designs.  Whether Tesla
	contributed would take deeper digging.  And, its not clear how
	meaningful patents, as such would be.  I fear much of
	significance may be buried in correspondence, or lost to
	history in other ways.
 
> 2. Don't know about Tesla's name on transformers, but in the Smithsonian
> Edison exhibit, part on Niagra Falls exhibit is a name plate from one of
> the original AC generators there.  It lists about a dozen patent
> numbers, ALL(!) in Tesla's name.  The exhibit may not be there now, as I
> last saw it several years ago during the period when the Smithsonian was
> totally ignoring Tesla.  Someone must have failed to notice those patent
> names!

	No one can know everything.
	At the risk of reupping the 'transatlantic leap' thread, the
	Exhibit at Marconi Beach, Cape Cod, specifically refers to the
	transformer originally installed there as a Tesla Transformer,
	or so i recall.

> >         Neglect winding resistance, neglect leakage reactance,
> >         rarely (if ever) see the magnetizing current, esp the
> >         first cycle surge mentioned...  These are all 'second
> >         order' effects, granted, but quite real, and of concern
> >         when handling KW and MW.
 
>         Anyone who has ever connected something as small as an unloaded
> 10 amp variac to the line has probably noticed the lights blink now and
> then,

	Or: dump a 15A breaker, as someone inquired of some weeks back.

> due to the initial inrush current caused by the DC component of the
> input voltage due to switching at other than 0° phase.  Not a second
> order effect at all!

	I think we are debating the definition of second order.  Perhaps
	a poorly chosen phrase on my part.  My point was that the
	casual 'turns ratio' explanation used in HS Physics ignores much
	of significance... 
> >         I'm not sure i understand 'pulse transformers' as 'ultimate
> >         power transformers'.  One is (typically) optimized for max
> >         bandwidth and 'fidelity' (if those differ), the other for
> >         max efficiency at One freq and economical performance.
> 
>         I mentioned pulse transformers because they are extremely wide band,
> and their performance is often limited by distributed capacitance within
> the transformer.
> 
> Ed