[Boatanchors] Using ac motor start capacitors in dc power supplies - wvdc question

[Greg Mijal]

Hi:
I just found a box of motor starting capacitors in my garage.  PPD film capacitor 15 uf @ 370 vac 50 - 60 hz.
My question is how do you calculate the maxium DC voltage capability of an AC rated capacitor and are there any trade-offs or gotchas! involved with DC service.
Thanks!
Greg
WA7LYO
Kinston NC