[DMcMahon]

I have been having at quick look at sourcing new suitable replacements for the four RC snubbers and see that it may not be quite as easy as it might seem.

I see from last years "TK 920 Exploding caps" post that the poster sourced (and I assume used) some Kemet devices. One of the forum reviewers was not keen on the Kemet parts for a couple of reasons, one being that they have a paper dielectric and he recommended polypropylene. They are a metallized paper dielectric technology which I think is old and in better capacitors superseded by Polypropylene film.

Personally I am not so sure I would be too unhappy with the Kemet devices for the reasons given by the reviewer, but there are 2 (maybe small points) about the Kemet device that might put me off a little.

1.They are rated at 250 vac, at least one of the snubbers sees 260 volts (from the 260 volt tapping on the mains transformer) I think on motor start, so ideally it would be good to get a higher rated ac volts snubber. The Kemet device is X2 safety rated so probably is fine. Of course the original Frako snubber is only 220 volts ac rated ! and in those days unlikely to have any safety/impulse voltage rating .

2. The Kemet device is only rated at 630 vdc which in this application is probably OK, but is low compared to the 2,000 vdc Frako rating.