George wrote:

The technology is actually 1970,s but it is way ahead of the old car
regulator. I shall remove the covers to the exciter and take some
pictures. but it will take a few days. Watch this space. The
alternator was driven in line by a similar sized 3 phase motor
continuously, to provide a smooth supply to a medium sized ICL
computer installation.


That rings a bell. We had such a setup in the machine room at BRA01 to
drive the 2980. It never worked though, and you wouldn't call a 2980
"medium sized" either. One of those little things - I knew it was
there, but never actually saw it, just heard it cursed!

Andy