What I understand:
- In simple DC circuits, this is a product of the current and voltage, such that 1 watt = 1 ampere x 1 volt
- I understand that a watt is a unit of power (change in energy per unit time) that describes the rate at which physical work can be done
- Reactive power is power for which current flow occurs, and that isn't actually used by the source. Even though it's not used by the destination, the intermediate current flow causes transmission losses, which is why it's undesirable. Hence why power factor correction exists, and why utility companies bill non-residential customers for a low power factor.
What I don't understand:
- Is reactive power truly unusable? Suppose I had a magnet coil in a fictitious AC circuit, that is purely
capacitivereactive, with no resistive component at all. It would exhibit purely reactive power flow. Wouldn't the coil produce a changing magnetic field, that I can use to deflect a nearby magnet (converting electric energy into kinetic energy)?
- Are watt and volt amperes dimensionally equivalent, just e.g. like km/s and miles/hour?
- If so, would using watts to denote apparent power be "technically correct" (and merely "wrong by convention")? If that's the case, then my understanding that VA is used instead of W, because it has a "documenting" purpose, by commenting exactly how these watts can be used. But this sounds strange, because then it seems like "not all watts are created equal".
(I know this question has been asked before, but none of the Q&As I found answered the precise points of confusion I had.)