# Re: good doorknobs for VTTC?

```Original poster: "Sean Taylor by way of Terry Fritz <twftesla-at-qwest-dot-net>" <taylorss-at-rose-hulman.edu>

> KVAR is kilo-Volts-Amperes-reactive
>
> Dr. Resonance

Just to expand on that . . .

The reactance of a capacitor, Xc = 1 / ( 2*Pi*F*C ), and the impedance
is -j*Xc.  F is the frequency of current going through the capacitor,
j is the imaginary unit, and C is the capacitance.

The imaginary power that a capacitor ABSORBS (from the negative sign
in the impedance) is:

Q = V^2 / Xc = I^2 * Xc, so

Q = V^2 *2*Pi*F*C = I^2 / (2*Pi*F*C)

Often times, power factor correction caps in power systems are rated
in kVAR, or MVAR to make calculations easier, i.e. if the power factor
is 0.8 and the load's apparent power is 1 MVA, 0.2, or 20% of the
apparent power is is reactive, or 200 kVAR.  A capacitor rated at -200
kVAR could then be put in the circuit to bring the power factor to
unity, and the apparent power to 800 kVA.

Probably a little more in depth that you wanted . . . but hope that
explains everything.

Sean

```