Electrical Generator

Check this article http://ecmweb.com/basics/basics-electrical-equipment-ratings

I guess it depends on where you live....

All of our military generators are always referred to by their kW ratings. Uses fewer letters so we can save on ink.

(The assumption of course is that the kW rating is for unity power factor only, and if you have less than that, you will need to do some math to find out whether the generator is up to the challenge.)

Anybody who knows that the current is limited by various factors such as the size of the windings, the rating of the over current protection device and the size of the cables connected does. Anybody who knows that were it powering a reactive load the current is out of phase with the voltage does. And anybody who knows that this source does not dissipate those kW from within itself does as well.

Actually here in the USA small electrical generators are usually rated in KW (Kilowatts) and larger electrical generators are rated in MW (Megawatts) while KVA and MVA are terms normally used for transformer size rating.

Well, you are at least partialy correct in that assessment, however, on further review, every one of the turbine-generators has KVA on the nameplate rating, along with what power factor that rating applies to, at least at the company where I work.

The MW rating only applies to power factor greater than 99%.

I was taught when i was a junior electrician, that generators require both ratings. In simple terms.

The max current is partially based on the max heat removal capacity. That is if you can keep the windings cool you can carry more current. (insulation and other components won't become damaged)

The max voltage rating is based on the insulation resistance of the windings. The better the insulation, the higher the allowed voltage.

Obviously, if you max out the insulation, you can't cool it as efficiently so both ratings must be considered.

The prime mover (steam turbine, IC engine, wind vanes, etc) has to supply the real power (kw)(real power) component.

So this can limit the maximum current for a given voltage as well. That is the simple reason why generators use kVa (apparent power)

Motors are rated for KW since you need to know how much real work they can do.