Originally Posted By: 1 FMF
http://en.wikipedia.org/wiki/Power_factor
also google power triangle
things get lost in translation.
the basic premise is watt = volts x amps, and watts is a measure of power. and power over time = energy in watt-hours or kilowatt-hours which you see reported on your electric bill.
but you and any company that uses electricity actually pay for "apparent power" which technically is based on the amount of current drawn and "used" and that is why a big deal is made about power factor correction,
because when a factory has poor power factor like when they have all induction motors that are only 50% efficient, that means there is high high reactive power and a lot of current drawn by the load is not used to do any useful work. That higher current draw results in higher transmission loss from the power plant to the load, which the power plant has to supply to begin with.
the power plant can't supply that extra current (power) without using extra fuel, which costs them money... which costs you money.
So they charge you for apparent power, as in kilo-voltamps (KVA) technically and not kilo-watts, even though is says kw-hours on your bill.
and is also why you will see many things especially in industry have a KVA rating instead of a KW rating, because the amps of the KVA is what will trip a circuit breaker.
This is what you get when someone reads Wikipedia then thinks they're an instant expert.
In general, nobody pays for VARS especially not residential. There can be penalties in industrial for a power factor lower than contract. KVAR does not translate to torque and does not cost the generator extra fuel. The gen exciter has to be turned up and the rating is reached sooner with less KW left in reserve. I'm not going to go on. You need to go to school for at least a couple of years.
Anyway it's a complex system. Reading the internet and thinking you're an engineer is just like reading it and thinking your a doctor and diagnosing your disease.