86.
This photo is labelled Transformer House Roof 5/9/21. However it appears to be the floor of the watertower tank, it is octagonal and in the right place relative to the SECR mainline. I’m not aware there was a transformer house in the lower storey of the watertower as it appears open in other photos and would have been an incongrous place to have sited electrical equipment. As far as I know, the main power requirements of the mill were provided by the DC generators coupled to the steam turbines. Typically, variable speed drives at that time would be DC and indeed many still were in the ’70s, there being a rectifier house in east mill pulp yard under part of no 1 pulp conveyor as later extended to the kraft beaterfloor. I believe No 3 machine was converted to a Cortina (thyristor?) drive system around the later ’70s.
