[Hugh R]

Are you sure its MFD or mFD? I don't believe you would have a Mega (M) Farad capacitor, as opposed to a micro (m) farad capacitor. An ampere is the rate of electrical flow (current) of one coulomb per second, an alternate definition is that a farad is one ampere-second of charge at one volt.

One Farad=Couloumb/Volts.

So .3MFD=X/600 volts, or 300,000FD=X/600, where

X=18,000 Couloumbs per second, not likely, that's 18,000 amps per second of discharge. More likely is

.3mFD=X/600 volts, or 0.000003 FD=X/600 volts, where

X=0.00018 couloumbs per second.

To get X=0.00018 couloumbs per second, I'd think with a 200VDC capacitor you'd want a .9mFD, 200 VDC capacitor to get the same "capacitance". But I'm not an electrical engineer so take it for what its worth.

The capacitors in old time distributors are measured in micro farads. At MIT once, I worked on capacitors that were the size of trash cans and they measured in Farads.