Stud-mount diodes (four in a bridge configuration) are protected by MOVs: one across the AC connections, one across the DC connections.
These MOVs are antique-looking finned affairs (a la selenium rectifiers). Both sport PN S01AAA?AAA (?=illegible) with Westinghouse trademark. The wiring diagram symbol for these looks like a zener diode with an extra arrow head (both arrow points touch, with the familiar "z" shaped line between them).
The AC supply voltage to the bridge is 75 rms. The bridge diodes are originally 100V/1A devices; I'm replacing with 400V/35A ones.
This rectifier drives a DC motor via 2 contactors: one for direction (by reversing polarity) and the other for "GO/STOP". The MOVs are to limit the kick from opening contacts, I presume.
Someone suggested that with such stout diodes available today that maybe the MOVs are not required.
If you think I need to keep the MOVs, how do I select new ones?
What say y'all?
Thanks,