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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