50 Hz 1500 Rpm Alternator Running At 1800 Rpm

[chaterpilar]

Hi !!,

 

Another 50hz/60hz question.. but this time for alternators.

 

I have seen at a site 1320 kva 50 hz 1500 rpm alternator coupled with a 1800 rpm engine and being used as a 60 hz source,

 

Now my question is what will happen to the ( 1320kva) rating of the alternator will it decrease or increase and what are the other effects on alternator...what would be the maximum current drawn out of this alternator if it is rated at 1800 amps at 50hz.

 

chaterpilar

[niallnz]

If the rated output current is 1800Amp at 50Hz then the rated voltage is 425V. Most 50Hz networks would operate at between 400V and 415V. If the alternator is run at 60Hz the I would expect the AVR will be adjusted to give a voltage of around 440V, but the rated current output will be the same at 1800Amps as this is limited by the temp rise of the winding insulation. But at 440V and 1800Amp the kVA will be 1370kVA.

 

Cheers

niallnz