Generator capacity
- Thread starter cppoly
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texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
No, you could only put 800 KW of resistive load on the machine. What the specs are telling you is that there is 1000 KVA of current capacity available in the generator windings but only 800 KW of engine power. You could drive a 1000 KVA load that has a .8 PF. Keep in mind that KW is power and that is what the engine sees.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
I agree with texie. But here is a more detailed explanation.
A generator's KW rating is based on the capabilities of the prime mover (e.g., the diesel engine). That will not be influenced by the power factor at which the generator is operating. Its KVA rating is based on the ability of the generator windings to reject heat to their surroundings. At a load of 800 KW that is purely resistive, there will be a certain amount of heat being released by the windings. If the load is 800 KW but there is some capacitive or (more commonly) inductive load also being supplied, the engine will be doing the same amount work, but there will be more current in the windings, and therefore more heat being released by the windings. A generator that is rated at 800 KW and 80% pf will have the ability to reject the amount of heat associated with 1000 KVA of total load, but it will still be able to perform only 800 KW's worth of real work. That is the difference between the KW and KVA ratings.
A generator's KW rating is based on the capabilities of the prime mover (e.g., the diesel engine). That will not be influenced by the power factor at which the generator is operating. Its KVA rating is based on the ability of the generator windings to reject heat to their surroundings. At a load of 800 KW that is purely resistive, there will be a certain amount of heat being released by the windings. If the load is 800 KW but there is some capacitive or (more commonly) inductive load also being supplied, the engine will be doing the same amount work, but there will be more current in the windings, and therefore more heat being released by the windings. A generator that is rated at 800 KW and 80% pf will have the ability to reject the amount of heat associated with 1000 KVA of total load, but it will still be able to perform only 800 KW's worth of real work. That is the difference between the KW and KVA ratings.
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