Various analogies have been used to describe power factor e.g. Beer with Froth
It is the supply of apparent power measured in volt amperes or kilovolt amperes (KVA) by energy companies, which is billed in watts (W) like active power. This makes Power Factor Correction (PFC) unit installation crucial, which guarantees the reduction of the amount of apparent power generated by your power unit.
Take a look at the scenarios below, you will realize how much active or true power your business uses vs. how much power your business pays for.
Horse Pulling Cart
A cart on a railway track is being towed by a horse that is off to the side of the railway track. The pull directly between the horse and cart is the apparent power (kVA). The effective work by the horse is the cart moving down the track, being the active or true power (kW). The pull at right angle to the track does no effective work and represents the reactive power (kVAr).
The horse would ideally pull the cart directly down the railway track so the apparent power equals the real power, thus minimising wasted energy.
Beer with Froth
A large beer is ordered to quench the thirst of a thirsty individual. The beer has some froth on top that does nothing to quench the individual’s thirst – this represents the kVAr (reactive power). The beer does quench the thirst – this represents the kW (real power). The total contents of the mug (the beer and the froth) represent the kVA or apparent power. The glass must be full of beer with no froth for the person to gain maximum benefit from the glass of beer. It is the same for maximum efficiency with power as the system should not be drawing any kVAr (or froth in the analogy).