Easy: loading 750kW cat in a 0.95pf bldg
- Thread starter julesm
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- Lockport, IL
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- Semi-Retired Electrical Engineer
The generator has the capacity to provide the 937 KVA. If the building only uses 789 KVA, then the generator will have spare capacity of 148 KVA. That said, the generator is still limited to 750 KW. So if the building's .95 power factor is based on a real load in excess of 750 KW, then the generator will not be able to handle the entire building. In other words, the "spare capacity of 148 KVA" I mention above has to be primarily "reactive power" loads, and not "real power" loads.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
My rough understanding of this topic:
You have two limiting factors in play: the alternator which can only provide so many KVA, and the prime mover which can only provide so many KW down the shaft to the alternator.
You cannot exceed either the KVA rating or the KW rating without putting some part of the system into overload. If the power factor of the load is really bad, then you overload the alternator with excess current, while the prime mover is loafing along well below its maximum power rating. If the power factor of the load is really good, then you overload the prime mover without reaching the current limit of the alternator.
-Jon
You have two limiting factors in play: the alternator which can only provide so many KVA, and the prime mover which can only provide so many KW down the shaft to the alternator.
You cannot exceed either the KVA rating or the KW rating without putting some part of the system into overload. If the power factor of the load is really bad, then you overload the alternator with excess current, while the prime mover is loafing along well below its maximum power rating. If the power factor of the load is really good, then you overload the prime mover without reaching the current limit of the alternator.
-Jon
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