Large S4EN25 Power diodes from the 1970's - anyone know thei

[dave]

I came across 4 power diodes on a power supply with date 1973 and
marked S4EN25. These are large things (~3cm across with 1cm bolt
fixing).
Just for historic interest, anyone have an idea what their rating
might be? I can't find anything datasheet-wise from google.

 

[legg]

On Sat, 02 Apr 2011 22:49:55 +0100, dave <dave@127.0.0.1> wrote:

I came across 4 power diodes on a power supply with date 1973 and
marked S4EN25. These are large things (~3cm across with 1cm bolt
fixing).
Just for historic interest, anyone have an idea what their rating
might be? I can't find anything datasheet-wise from google.

You can get the approximate ratings from those of the power supply in
which they are used, including switching speed.

It would help if you can pull a mfr logo off the part, and off the
power supply - a paper search is not as elementry as google.

If you could make more accurate measurements, and identify the actual
thread used on the stud, it might narrow things down, as well.

SxENxxx may be a number used by Westcode.

RL