S.M. asked in Science & MathematicsEngineering · 6 years ago

# what is the meaning of a 400V,250KVA,0.8 PF lagging,2-pole,3-phase,60Hz synchronous generator?

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• Paul
Lv 4
6 years ago

Correction...the Power Factor refers to the power factor of the generator itself, assuming a purely resistive load, and like all generators, it consists of a bunch of windings, so it is inductive. Remember the mnemonic CIVIL means that in inductive circuits, V leads I, or that current lags voltage.

I was not sure about the number of poles...it says "2 pole", not "two sets of poles". Certainly 1800 RPM is very common in 60 Hz generators...rotors tend to fly apart at 3600 RPM. Thanks Steven.

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I think all AC generators are synchronous. To parse the words:

*400 volts probably means that the phase to phase voltage is 400 volts, and phase to neutral is 230 volts.

*250 KVA means 250 Kilo Volt Amps. Generators are rated in KVA, not watts, due to the influence of power factor.

*0.8 PF means that the generator is designed for a reactive (inductive or capacitive) load where actual power is 0.8 of the KVA value.

*Lagging means that the current lags the voltage (ie: an inductive load).

*2 pole means that there are two poles, so it produces one complete cycle per rotation, so it must turn at 3600 RPM for 60 Hz output.

*60 Hz means that it is intended to generate 60 Hz at 3600 RPM.

*Synchronous means that the output frequency is locked to the rotation speed.