Why do we use kVA instead of kW to rate alternators and transformers?

Related questions

1. How do you calculate CC to horsepower?
2. How many horsepower is a Nascar?
3. How much HP can a human produce?
4. Do turbo engines last as long?
5. How many horsepower is 250 cc's?
6. Is PS the same as HP?
7. Is PS and HP the same?
8. Is a v6 engine better than a 4 cylinder?
9. Is a 4.0 liter engine a v6?
10. Why is BHP called brake horsepower?

Tags

1. #winding
2. #rating
3. #copper
4. #losses
5. #transformer
6. #while
7. #current
8. #depends
9. #insulation
10. #powerfactor
11. #which
12. #passing
13. #depend
14. #determine
15. #thats
16. #voltage
17. #through