kvar formula

[OldNewbie]

Can some one please point me in the right direction? I'm looking for the formula to convert a known KVAR rating on a capacitor to microfarads.

For instance.... 500 kvar @ 7000volts= microfarads ?

Thanks,

Old

 

[winnie]

1) capacitive reactance is given by Xc = 1/ (2 * pi * f * C); the result is in Ohms reactive.

2) the reactive current that flows through a reactance is simply V/Xc; reactive power is given by V^2/Xc (this is just standard Ohms law stuff)

So 500000 = 7000^2 / Xc therefore Xc = 98 ohms

98 = 1/ (2 * pi * f * C) = 1/377 * 1/C therefore C = 1/(377 * 98) = 0.000027 F = 27uF

Converting the above into an equation that takes V, f, and VAR as input and produces capacitance as the output is left as an exercise

-Jon

 

[OldNewbie]

Thanks, Winnie.

Just the info I needed. I'll put it to good use.

Old