Enermax had once some fans with auto-restart function.
Capacitors can't store AC and aren't used for some "startup extra power".
(though variable frequency drives can add capacitance to provide some start up current, but they usually also have soft start)
Single phase AC motors often use capacitor to create phase shift for secondary winding, which is needed to create rotating magnetic field to get rotor moving.
With just single winding, magnetic field would be just switching polarity.
Hence rotor might not start moving at all, or even to wrong direction.
Three phase AC gives that rotating magnetic field naturally.
Also capacitors can be used for power factor correction.
While households are usually charged only for consumed real power, anything lot consuming like industry has to pay for full apparent power and hence reactive power from inductances matters.
And you cancel current component from inductance by adding capacitance in parallel with load.
I don't know what you are getting at.
Enermax having had fans with auto-restart function has nothing to do with anything I've posted.
AC power, charging capacitors really it makes no difference. Nor does it matter that caps are used to help get motor spinning without power source overloading.
This is computer forum so let's keep it about computer fans. Sorry if I lead use off topic.
Only reason I posted about startup load and running load is computer fans generally only give running load rating, not the many times more power the draw starting up or impeller is stopped.
Reality is our fan motors pull several time if not many times more power starting than they do running.
In all the times I've heard of members loosing fan headers, I can't think of one that happened once fans were up to speed. They all say it either happened at startup / noticed fans were not running after startup. They had fans cooling when they shutdown system. But didn't have them when they next started system. Always seems fans headers went out when fans were starting to spin and drawing the several times more power then they do once they get going.