# What exactly reactive power,active power and its effects on alternator operation?

Active power is that which performs real work. Reactive power is the oscillatory component that does not perform real work but does consume capacity in the electrical system. Reactive power is associated with capacitors and inductors in the AC system. Consider that the ac voltage and current waveforms can have any arbitrary phase relationship. Apparent power is simply the multiplication of current and voltage magnitudes. (For 3-phase circuits, a sqrt(3) gets into the mix depending on your choice of voltage measurements.) Active power is the real component of apparent power, due to the component of the current that is in phase (or anti-phase) with the voltage. Reactive power is the imaginary component of apparent power, due to the component of the current that is in quadrature with the voltage. Power factor is the active power divided by apparent power. Reactive factor is the reactive power divided by apparent power. Having a low power factor on your electrical system reduces the amount