What does 4000 VA mean?

CJW8 wrote:
I have traveled a large part of the world and only in the USA are generators and inverters badged with WATTS. Everywhere else they are badged in VA. I believe it is purely a marketing ploy to attach a bigger number.

That could be for small generators for home a RV-ing use. Large gensets (for prime power or standby power) are always rated in KVA. Kinda like in years past, home compressors had hugely inflated HP figures on them until the regs. changed.

VA (or KVA) will tell you how much current can be produced or handled by a generator, transformer, etc. or wire gauge. If you look at an AC motor nameplate for ex. (which have a PF less than 1.0), the full load amps will be indicated which can be used to determine if a transformer, or gen. will be adequate (notwithstanding starting inrush current for a single motor). Power companies are highly interested in knowing what a commercial or industrial customer's power factor is because it requires them to use heavier gauge service wire and larger KVA transformers than power consumption in watts would indicate. Sometimes they install a meter that measures PF and a customer will be charged for having a low PF.

Taking a look at compact fluorescent lamps, a 13 watt-er for ex. has a current indicated on the lamp of 175 ma. But 120V x 0.175A = 21 watts (meaning they have a rather low PF). So where do they get the 13 watts from and do the new smart meters charge customers based on current or is it true KW like with the old dial meters?

Then there are the terms "apparent" and "imaginary" power...