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Re: Power Factor Correction weirdness?



At 09:04 AM 02/11/2000 +1200, you wrote:
>Hi Terry ;)
>
snip...
>> 
>> Cpfc = ( Vo x Vi ) / ( 2 x pi x f x Vi^2 )
>> 
>> Where
>> 	Cpfc = Power factor cap value in Farads
>> 	Vo = Rated NST output voltage in volts
>> 	Vi = Rated NST output current in amps
>> 	pi = 3.14159...
>> 	f = AC line frequency (50 or 60Hz)
>> 	Vi = AC input voltage (120 VAC)
>> 
>> For a 15kV/60mA transformer you get:
>> 
>> ( 15000 x 0.06 ) / ( 2 x 3.14159 x 60 x 120 x 120 ) = 165.8uF
>> 
>> To get "exact" you have to take all the non linearities, timing, and such
>> into account which is a few orders of magnitude harder but this equation
>> seems to do fine...
>> 
>> Comments, suggestions,...
>
>only one - it would be useful to use I for current instead of V  :)
>
>Regards,
>Malcolm
>

Hi Malcolm,

	I was just following our long standing Tesla list tradition of never being
able to get a posted equation right the first time no matter how hard one
tries ;o))  It was written correctly in my notes and everything....  My
second attempt at the equation follows...

 Cpfc = ( Vo x Ii ) / ( 2 x pi x f x Vi^2 )
 
 Where
 	Cpfc = Power factor cap value in Farads
 	Vo = Rated NST output voltage in volts
 	Ii = Rated NST output current in amps
 	pi = 3.14159...
 	f = AC line frequency (50 or 60Hz)
 	Vi = AC input voltage (120 VAC)


Cheers,

	Terry


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