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).
Analysis of voltage drop in headlamp wiring circuits for various chassis models.
| Identifier | ExFiles\Box 168b\2\ img224 | |
| Date | 3rd March 1931 | |
| -2- EPCB/AD6.3.31 contd. (c) Between the head lamp fuse and head lamps 1.0 volt the lesser value of the former figure being due to charging current and the greater value of the latter figure being due to the fact of increased head lamp voltage and current generally. The above figures being for chassis 20-EX, the loss of P.D. between the head lamp fuse and the head lamps includes loss through the Lucas two-way switch. In the case of chassis 14-EX, the loss of P.D. due to 60 watt head lamps lighted from the battery was (b) Between the main emergency fuse and the head lamp - 1.0 volt and (c) Between the head lamp fuse and the head lamp - .2 volt. making a total of 1.2 volt. What we are concerned with in the above is the wiring through from the switchbox via the distribution box to the head lamps, as the remaining part of the circuit is all 90/36 and in any case is not involved in the lighting of the head lamps to any appreciable extent when the dynamo is running. In the case where there is no head lamp to central lamp changeover switch, the standard wiring from switchbox to distribution box and from distribution box to each head lamp individually is 40/36. Sometime back we made a move, for the express purpose of reducing the voltage drop, to have the 40/36 from the switchbox to the distribution box altered to 90/36 but were informed by the D.O. that this was not practicable because, not only would it upset the colour scheme but the larger cable would overcrowd the conduit. Our move was based upon the argument that that one 40/36 wire | ||