From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
From Springfield to Derby regarding the supply of Bifocal Headlamps and the substitution of 12-volt bulbs with 6-volt versions.
| Identifier | ExFiles\Box 61a\1\ scan0369 | |
| Date | 23th October 1928 | |
| X4477 -/HS{Lord Ernest Hives - Chair} Na{Mr Nadin}5B102328 October 23rd,1928. To Rm.{William Robotham - Chief Engineer} Derby From Na.{Mr Nadin} Springfield RE: HEADLAMPS Further to my memo of October 6th, Na{Mr Nadin}2B10628, we have received a letter from the people from whom we have ordered the Bifocal Headlamps, reading as follows:- "In your letter you indicate that you would like to have the Tilt Ray lamps we are making for you equipped with 12 volt bulbs. Up to date there have not been any satisfactory 12 Volt bulbs made in the two filament type that is necessary for depressible beam headlighting. In addition to this we realize that the people abroad are accustomed to driving behind bulbs of extremely high candlepower. It is therefore, our suggestion that these lamps be equipped with either 32 c.p. or 50 c.p. filaments for the driving beam but in both cases they will be for use on 6 volt systems." In view of the fact that 12 volt bulbs have not been produced commercially, we are sending the lamps with 6 volt blubs, which will give you an opportunity of testing the device. It does not seem easy to connect the lamps in series, but for the purpose of your experiments, perhaps a 6 volt battery might be used. TN/B | ||