A typical syllabus of the 1920's for a HMS Vernon/HMS Defiance course in W/T, took just over 38% on the Instructional Time allotted to the course for Petty Officers dealing with the subject of "POWER SUPPLIES".

The senior telegraphist in a ship was as directly responsible for the provision of power [for his sets] as he was for ensuring that correct procedures, frequencies and power outputs were adhered to.  Power for W/T equipment was not on 'tap' and in some of the Dreadnoughts, no fewer than ten different and separate machine power sources were needed to fulfil the demands of the equipment.  The knowledge of rotaries, alternators, generators, ring-mains, and batteries were prerequisite's, and, whilst serviceable [free from defects] wholly the responsibility of the W/T branch {for their equipments}.  If we added  the skills necessary for the use of wavemeters, oscillators, buzzers, aerials, trunkings, transmitters, receivers etc, etc., you wouldn't be surprised to hear that the actual instructional sessions for Morse training, organisation, coding/de-coding classified messages, administrative and the procedural parts of the wireless-world were just 15% of the overall time on course. These two files are typical of syllabus input WT SYLLABUS HAND START MACHINES.pdf and WT SYLLABUS BATTERIES.pdf

With this in mind, have a read of the following article.

Today we take for granted power supplies per se.  Few know that as the switch is made, AC is applied directly to machinery requiring electric power to function, but does it matter anyway? - if it works it is OK! . Many many years ago, when electric power could be developed by using a dynamo powered by an engine (the likes of the Ironclads in the 1860's manifest in the form of HMS Warrior's steam engines),  DC (Direct Current) was the end product, and the only CURRENT needed to service the late 19th century electrical equipments. That was the status quo for many years into the 20th century until friend Marconi and Captain Jackson developed their wireless telegraphy equipments, and that required a change of thought.  Using various battery packs of, to say the least, dangerously high voltages and lethal currents, they could drive an alternator which would produce AC (Alternating Current) a source needed for their new found technology.  Providing they could re-charge the battery packs, they could continue indefinitely with their experiments, and since the modus operandi of the navy was DC., there was an almost infinite supply available for re-charging.  Later on, the DC ring main of the ship was used to power-up the alternators, and the batteries became emergency supplies if and when the ring-main failed. That train of thought locked the navy into DC, and from the early 20th century right through to the 1950's, some British warships were producing DC as the ring-main supply.

By the late 1940's early 1950's there were, incredibly, thirty two AC Supply Outfits in the Fleet all of which are shown in the following two PDF Files.  To really understand the various configurations whether for W/T of for Radar, one needs to look at each of these Supply Outfits and specifically to the paragraph of (WHERE FITTED).  Fortunately, after this time, ships became AC (Alternating Current) generators and thus, the need for AC Supply Outfits, just like the wavemeters and the battery outfits, soon died-out leaving only the diesel generators to take over for limited supplies of AC should the ships ring-main fail.  Here then are those AC Supply Outfits AC SUPPLY OUTFITS.pdf - AC SUPPLY OUTFITS TWO.pdf AC Supplies Late 1920 to Early 1950.pdf

Some other sections on this site have their own stories about batteries to tell.  Batteries were not only used to help generate AC supplies for mains purposes, and when valves were introduced, each valve had to have a separate battery for its anode circuit and another one for its filaments [see the Receiver page].

The following two files show battery supply outfits BATTERY OUTFITS.pdf and Battery outfits Late 1920 to Early 1950.pdf.

Then comes  the AC fit ships from the 1960's on.  They are typical fits of a Fleet destroyer/frigate, and a heavy destroyer. Small notes are shown covering emergency power.

Switchboards of the twenty first century will be much more streamlined with computer control, but they will be doing the same essential work as did the old 1960-1980 generating plants did.

The 'old' Ark Royal, a rather large 'lady' was built as a DC ship - see below. Had she not been converted/added to, she would not have coped with a major ICS fit.