Early electricity supplies to the consumer could be either Direct Current (DC) or AC (Alternating Current) the generation being by water - hydro electricity, coal gas - gas engine, or steam raised by coal firing. Gas engines were common where a town had a gas works stating the obvious. In the case of Newton Abbot coal was used, being at a major rail head, to produce steam to power a reciprocating steam engine coupled to DC Generators.
	When I joined the station had a 'Belliss and Morcom' three stage reciprocating steam engine with a 200 kw DC generator attached. This fed an open 500 volt switchboard with two? feeder connections to hotels in Newton Abbot. There was a 600 amp battery bank associated with the DC switchboard to provide emergency supplies. This supply remained available until the mid sixties.
	As this section of the station was constructed before any interconnection to other generating stations occurred it seems probable that this was part of the original equipment enabling start up of the auxiliary plant serving the boilers, turbines and riverside pumps from the 1920's.
	DC Motor control (and variable speed if required) is relatively simple and robust. From the above you will deduce that the steam engine had to run initially to provide auxiliary supplies and as part of the Low Pressure build (1920's) 400 kw rotary converters were installed to convert the generated AC back to DC to maintain DC supplies without the steam engine itself running.
	The setup as installed meant it was possible to carry out a 'black start' - that is without any AC connection the station could be started up with the wettest of steam turning the steam engine in turn energising the DC switchboard and enabling DC auxiliaries to be started sequentially to gradually raise steam to run a main turbine. We did it on at least one occasion and brought the station from a cold shut down to a generating condition with a box of matches and an oily rag - it worked and took around twelve hours if my memory serves me right.
	Two Rotary Convertors were installed with an individual capacity of 400 kw. They were connected via transformers to the 11 kv cellular switchboard which itself formed part of the Low Pressure installation. Two running converters were required to secure all DC supplies.
	When heavy DC motors were started the RC's would give out a squeal like a pig! You knew they were working. The open 500 volt switchboard needed care - it was virtually un-maintainable. Completely unacceptable in today's H&S environment.