On Monday, November 14, 2016 at 4:13:07 PM UTC-5, wrote:
"Two caps in series must be calculated, but keeping it very simple, if two 20uF @ 450V are connected in series, the actual capacitance will be 5uF @ 900V. "

That's not what I "heard". It should be 10 uF.

(C1 x C2) / (C1 + C2) = Working Capacitance is the equation I have used these many years.

Example 1:

10 x 10 = 100
10 + 10 = 20
100 / 20 = 5

Example 2 (from the link):

10 x 22 = 220
10 + 22 = 32
220 / 32 = 6.875

At least where I come from.

Peter Wieck
Melrose Park, PA