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Re: To Jason: Best Sparks




From: 	Jim Fosse[SMTP:jim.fosse-at-bjt-dot-net]
Reply To: 	jim.fosse-at-bjt-dot-net
Sent: 	Thursday, September 18, 1997 1:05 PM
To: 	Tesla List
Subject: 	Re: To Jason: Best Sparks


>From: 	Thomas McGahee[SMTP:tom_mcgahee-at-sigmais-dot-com]
>Sent: 	Wednesday, September 17, 1997 9:12 AM
>To: 	Tesla List
>Subject: 	To Jason: Best Sparks
[snip]
>MOST Tesla coils will also give those extra long arcs the *instant*
>they
>are first turned on. The exact cause is not fully known,
[snip]

Fr. Tom,

	Don't forget that when the system was last turned OFF, the
core of the mains transformer was left in some polarity of
magnetization (assuming that you didn't turn it off exactly at the
zero crossing of the mains power).  The next time it's turned on, you
have a 50/50 chance of applying power that will produce flux in the
core in an opposite direction to it's existing polarity. 

This causes the inductance of the core to be effectively canceled out
for the first half cycle of the mains power. The input current to the
transformer in no longer limited by the inductance of the primary, but
by the resistance of the primary which is much lower. This huge input
current then produces a higher than normal output voltage from the
transformer.  

This effect is also responsible for blowing circuit breakers when an
unload transformer is plug in.


	Regards,

	jim