My book had these two solved examples that gave contradictory replies.(adsbygoogle = window.adsbygoogle || []).push({});

The power output of an alternator is 100 kW. Now if the tangent of pf angle is 0.8 lagging, the KVAR rating must be -80KVAR.

I drew phasor and got this.

I took it that since tangent is negative. Now tangent is opposite divide by adjacent, so negative tangent mean opposite component angle - adjacent component angle is negative, it means that opposite lags adjacent component.

But then the next section had this example:

The power output of an alternator is 40 kW and KVAR component is - 25. if theta is power factor angle then the value of tangent of theta, is 0.625 leading.

Here if we see then KW is positive in phasor and KVAR is negative in phasor. So tangent of theta is tangent of (-25/50) is -0.625. But it should be lagging since KVAR is lagging KW. So is book wrong in saying tangent of power factor angle is leading 0.625.

Is first phasor right or second phasor? Is tangent of power angle leading different than power factor leading?

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# What is tangent of power factor angle for an alternator?

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