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).
Recommendations for side lamp bulb wattage and analysis of the electrical system's total ampere load.
| Identifier | ExFiles\Box 166\4\ img042 | |
| Date | 1st January 1930 | |
| EFC/ATB.1.30 contd. -2- for side lamp use, e.g. in the Phantom II Instruction Book No.5 page 78. The reasons we now recommend lamp bulbs of the 4 watt type are (1) The use of the central lamp enables us to reduce the power of side lamps to a minimum, as side lamps are not, in these circumstances, required as driving light. (2) It is desirable, from the point of view of conserving the output of the dynamo-battery system, to utilise bulbs of as small a wattage as possible. The total ampere load of all the recommended lamp bulbs simultaneously, except the central lamp and inspection lamp bulbs, is 9 - 9½* (excluding battery ignition current) and for reasonably satisfactory operation with the present standard dynamo this load cannot, in our estimation, be appreciably exceeded, though we are aware of the move to use 60 watt head lamp bulbs, which between them make an additional load of 4 amperes on the system. EFC. | ||