>The energy stored in that capacitor isn't available for you to use. Well, it's only available to use when the power fails or something like that. When you fi

>The energy stored in that capacitor isn't available for you to use. Well, it's only available to use when the power fails or something like that. When you first power up, it requires a finite amount of time for the storage/filter capacitor(s) to charge up to their full design voltage before your circuit really works as intended. Later when you disconnect incoming power, the stored energy from the capacitors does continue to supply DC power to your circuit for a finite amount of time afterward, at declining voltage as the capacitors are drained. >This is evidently something similar but for AC. It stabilizes the AC voltage / phase because its momentum pushes back against whatever tries to disturb it. Yes, I think this is it. Seems to me these massive AC stabilizers would help maintain frequency and voltage during unavoidable events where the grid dropped below nominal, by more gracefully dropping when necessary as the grid sucks momentum from the stabilizer down to its own level at the time. And if power completely failed it should end up in a more graceful "wind-down" as all momentum for all stabilizers require a finite amount of time to come to a complete halt, letting whatever limited amount of stored energy they contain be delivered to the grid until there is no more.