AJ hope you are keeping well,when I worked at your place well over 50 year ago you were converting a lot of those early 955s to direct start,I cannot remember ever seeing a 24 volt Bosch generator on them or any other Cat either for that matter and there was some amount of machines coming in at that time,there used to be 6 volt Bosch generators on the starting engine models and I can remember that there were two different regulators one for a battery and one for without,the generators and starters you used to were not Delco or Bosch but for the life of me I cannot remember their make,talking about electrics do you remember the late Jim Sweeny's old D8 that was on a site that you and I were working on somthing else,the pony would not start and he was asking us to get it going for him,you went over to have a look and asked him if the mag was alright and he replied that it was rebuilt by the finest Caterpillar electrican in the country and you said to him he would want to be pointing to the drivers bicycle laying up aginst the Cat,there is nearly as many wires on it as that bicycle and its got electric light,ah happy days AJ.
Tony

The generators,regulators and starter motors we used were Simms,they were home grown and a lot cheaper than Delco,I don't think any of the early 955's came with a factory direct start and like you I cannot remember any with Bosch 24V systems on them,if they had been converted anything could have been used,proper pig to convert they were too but it increased the resale value quite a lot so worth the aggro,they sold as fast as we could turn them out.we put the regulator on the left of the battery compartment looking in from the back.
AJ

The US built machines offered Direct Electric Start option as of s/n 12A3888. Used 24v American Bosch generator and 24v Delco Remy Starter.
I am not familiar with Simms but at least you didn't use Lucas (Prince of Darkness) junk.

I have a Simms manual wind up starter, they are used on both gas and diesel engines, who needs a battery?

strumco.com/air-starters/kineteco-spring-starters/

Hmmm, formerly made by Lucas, guess they gave up on electrons.

I have it on good authority that Simms lights were also fitted to UK Cats.

Simms manufactured a lot of automotive gear before being absorbed and nationalised and ruined and I think at one time the founder had a tie up with Bosch eg., for magnetos - which had to be broken due to the war.

Here is the brochure for one I have that allegedly came of a 1950's D2 5U

Borrowed from Wiki

Simms

In 1913 Frederick Richard Simms started Simms Motor Units Ltd, which in the First World War became the principal supplier of magnetos to the armed forces. In 1920 the company took over a former piano factory in East Finchley, north London.[10] During the 1930s the factory developed a range of Diesel fuel injectors.[10] In the Second World War the company again became the principal supplier of magnetos for aircraft and tanks, also supplying dynamos, starter motors, lights, pumps, nozzles, spark plugs and coils.[10]

The East Finchley factory continued to expand after the war, eventually reaching 300,000 square feet (28,000 m2), and the company took over many other firms.[10] Simms Motor Units was itself taken over by Lucas in 1968 and integrated within the CAV division.[10] Manufacturing in East Finchley was steadily run down and the factory closed in 1991 to be redeveloped for housing.[10] It is commemorated by Simms Gardens and Lucas Gardens.


Cross-licensing agreements

In the 1920s Lucas signed a number of cross licensing agreements with Bosch, Delco and most of the other automotive electrical equipment manufacturers in Europe and North America. In addition, these agreements included a non-competitive clause agreeing that Lucas would not sell any electrical equipment in their countries and they would not sell electrical equipment in Great Britain. By the mid-1930s Lucas had a virtual monopoly of automotive electrical equipment in Great Britain.

With a monopoly in place, Lucas proceeded to supply electrical equipment that was commonly cited as the best reason not to buy a British car.[11][12]

Thanks Josh,
That was the Lucas that I'm familiar with.