# Difference between reactive load and source?

Probably a silly question, but I am coming across terms like reactive power load and reactive power source in some articles in web. Does it matter if a reactive component is a source or load? Say between an inductor in induction motor and coils in synchronous generator, is there any difference in the way they work?

Also, direction of current tells if a component is load or source in DC. How to get similar sense in AC, and understand if something is load or source?

• You can't just know in AC unless you do the math. Commented Jun 16, 2020 at 4:39

## 2 Answers

The concept of reactive power was invented to explain why the power consumed by an indiction motor is not simply voltage multiplied by current. Since the motor is inductive, the convention is to say that inductors consume reactive power and capacitors supply it. We say that a synchronous generator functions as a capacitor because it can be a source of reactive power consumed by an induction motor. The terminology is difficult to follow, because the concept of "consuming" reactive power is not technically correct, but it is convenient for the situations in which it is used.

Here is an explanation of the naming convention.

See also: What is reactive energy?

I think it is hard to make static definitions as you propose, reactive components are not strictly passive or active in the basic sense of the word. As you said every cycle it changes due to the nature of alternating current. Things like inductors and capacitors store energy and can release it later so they are not strictly passive.

a capacitor "produces" reactive power and inductor is a load, if you want to strictly define them as sources and loads then the sign of the reactive power term of the phasor is as close as you can get(or the imaginary part of the power being negative)