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FW: transformers




From: 	Peter Electric[SMTP:elekessy-at-macquarie.matra-dot-com.au]
Reply To: 	elekessy-at-macquarie.matra-dot-com.au
Sent: 	Saturday, August 30, 1997 4:42 AM
To: 	Tesla List
Subject: 	Re: transformers

Tesla List wrote:

> From:   Mad Coiler[SMTP:tesla_coiler-at-hotmail-dot-com]
> Sent:   Friday, August 29, 1997 11:33 AM
> To:     tesla-at-pupman-dot-com
> Subject:        Re: transformers
>
> >From:  Jim Fosse[SMTP:jim.fosse-at-bjt-dot-net]
> >Reply To:      jim.fosse-at-bjt-dot-net
> >Sent:  Thursday, August 28, 1997 9:16 PM
> >To:    Tesla List
> >Subject:       Re: transformers
> >
> >
> >>From:         Mad Coiler[SMTP:tesla_coiler-at-hotmail-dot-com]
> >>Sent:         Thursday, August 28, 1997 11:57 AM
> >>To:   tesla-at-pupman-dot-com
> >>Subject:      Re: transformers
> >>
> >[snip]
> >>  Well, I have never tried hooking different voltages in parallel
> >>becuase I have gone by the following:
> >>  If you hook 2 xformers together directly in parallel that have
> >>differing voltages then you have just made a complete circuit.
> >[snip]
> >>
> >>Perhaps ASCII could help
> >>
> >>            ~1 ohm
> >>       +    1000V    -
> >>       ---~-~-~-~-~---
> >>       |             |
> >>       |             |
> >>    +  0             0  +
> >>       0             0
> >> 9000V 0             0 7000V
> >>       0             0
> >>    -  0             0  -
> >>       |             |
> >>     A |             |
> >>       ---~-~-~-~-~---
> >>       -    1000v    +
> >>           ~1 ohm
> >>
> >MC,
> >       This would be valid IF the transformers acted as voltage
> >source. They do not! Remember, the arc they are designed to run has
> an
> >impedance of ~5 - ~400 ohms. The have to be limited or they would
> draw
> >an enormous amount of current based on V/I.  So take you schematic
> >above and substitute either a Thevanin (sp?) or Norton equivalent for
>
> >both transformers and run Kirkoff's rule again. (the sum of currents
> >into a node must equal 0 and the sum of voltages around a loop must
> >equal 0.)
> >
> >>I hope you can make sense of this and see that if you start at point
> A
> >>and go CCW to the right, add up all the volatges across the wires
> and
> >>other neon that it equals the 9000V neon.
> >>
> >>These laws are what they teach us in college and they say for
> example
> >>that KVL MUST ALWAYS be valid, it's impossible to defy KVL.
> >Except, when you have an invalid model. If the results of your
> >calculations seem impossible, ALLWAYS suspect your model!
> >
> >       Regards,
> >
> >       jim
> >
> >
>
> Jim, thats a very intersesting point. I had thought about the neon's
> current limiting abilities as I was writing but wasn't sure how that
> effected them. I am intersted in hearing what actualy happens -
> anyone?
> You say above that my model won't work because I am using ideal
> voltages
> sources, and I know they are not! But they aren't really current
> sources
> either, are they? I mean they don't adjust there output voltage to
> supply current. The only other value is the resistance (impedance?).
> Does this somehow change? Is there some sort of 'sensing coil' that
> can
> adjust total inductance? And, Jim, I know that you check your model
> when
> you get strange results, but I am only trying to prove that hooking
> the
> transformers together isn't the best way to go, wich my 'model'
> although
> not ideal, does - unless there are coilers that have proved that it
> can
> be done? But, I am curious and will try and compute Norton or thevenin
>
> as you proposed and see what they say about the whole thing.
>
> Nortonizing wires and thevenizing toroids (?!?) in Ohio,
> Mad Coiler
>


NST's are basically current sources. The closer you get to 60Ma, the
closer the output voltage gets to zero. When connected to an average
Neon sign, the voltage drops to a few hundred volts.

Things may get more complicated if you have resonant charging though.

Cheers,

Peter E.