Some time ago, I bought a 1940's style battery charger at a Wessex SEC crank up. The intention is to run it off an appropriate stationary engine & dynamo (110 volt) It is very pretty and looks far older than its years, the style being early thirties.
I gave it an initial clean up and check over, noticing that the rectifier valve was missing, but otherwise it was very complete & certainly worth further investigation. On the front was a little badge that said "Ray Engineering, Bristol." Now, I knew where they were as I did my time in engineering at a small factory just up the road from them. Passing by, I saw they were still there and returned with the battery charger in the hope of finding a circuit diagram. After an initial "we make plastic knobs, not battery chargers", someone a good deal older was found who knew that they had done so long ago & I was ushered into the foyer to await developments. There on the wall was another, identical except for the pristine paint, polished brass and tag saying "Battery charger, Circa 1952")
The MD appeared, enthused, said decisively that all the paperwork had long since been chucked away - but they did have a box of left over bits from the restoration of the one on display, So over I go again this morning to collect same. A useful lot, including a valve, some terminal knobs and a switch that I needed.
Still no circuit diagram though. Is there perhaps a generic source for such things ? I know you can get books of circuit diagrams for old TV/s.