# RE: 3 phase converting

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• Subject: RE: 3 phase converting
• From: "Tesla list" <tesla@xxxxxxxxxx>
• Date: Sat, 22 Jan 2005 10:13:55 -0700
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`Original poster: Harvey Norris <harvich@xxxxxxxxx>`

`--- Tesla list <tesla@xxxxxxxxxx> wrote:`

`> Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>`

```> However, say you have two coils and you want the
> phase of the current
> through one to be 90 degrees away from the phase of
> the other.  Could you
> not just put an appropriate capacitor in series with
> the one coil.  Say
> that the coils have an impedance of R+jX..
>
> Make sure that R = X...
>
> You'd put a capacitor of impedance -j2X in series,
> so one leg would have
> impedance R+jX and the other would have impedance
> R-jX.  Since R=X, the
> current through one coil will be lagging the voltage
> by 45 deg, and the
> current through the coil with the capacitor will be
> hence 90 degrees apart.
>
> If the inductance is large compared to the
> resistance, then a capacitor of
> just -jX should work.  If R<<X, then current through
> one coil is 90 degrees
> lagging, and the current through the other coil will
> be in phase.
>
> If you want balanced currents, you might need to
> fiddle a bit with Ls and
> Cs to get the phases and amplitudes right.
In the case where the reactance is cancelled by -jX,
there will be a voltage rise given by the acting q
factor. To obtain equal currents on both coils it
would be necessary for the reactive side to be inputed
from a transformer that delivered a voltage equivalent
to that made by the resonant side. Hence the reactive
side becomes very innefficient compared to the
resonant, as it takes q times more amperage on that
branch to accomplish the same amount of magnetic flux.
HDN```