Vfd 5 years in storage capacitor reforming?

[Muzzer]

The oxide layer that provides the insulative layer within the electrolytic caps will degrade slowly with age if there is no voltage applied. This is initially formed during manufacture and can be "reformed" by applying voltage after storage. The reason for doing this slowly (by ramping up the voltage slowly with a series resistor to limit the current) is because an unformed capacitor could break down if the full voltage is applied suddenly. That could become quite exciting and expensive.

Here's how the big boys do it: https://library.e.abb.com/public/79a...ming_Rev_G.pdf

Having said all this, I've been developing VFDs for over 25 years now and I've never bothered with the process nor have I ever had a failure.