A three-phase alternator is operating at 450 volts with the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter reading would increase by __________.

In a 3-phase AC circuit, real power is $P = \sqrt{3} \times V \times I \times \text{pf}$. For $\text{pf}=0.7$, $P_1 = \sqrt{3} \times 450 \times 300 \times 0.7 / 1000 = 163.68\text{ kW}$. For $\text{pf}=0.8$, $P_2 = \sqrt{3} \times 450 \times 300 \times 0.8 / 1000 = 187.06\text{ kW}$. The power increase is $187.06 - 163.68 = 23.38 \approx 23.2\text{ kW}$.