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).
Testing and performance of a Lucas head light dimmer switch with high-power lamps.
| Identifier | ExFiles\Box 61a\1\ scan0126 | |
| Date | 21th October 1921 | |
| X. 4291. W/S. C/Bk.{A. Birkett - Commercial Manager} from EFC. EFC1/T21.10.21. X.4291 - LUCAS HEAD LIGHT DIMMER. We have your note Bk{A. Birkett - Commercial Manager}14/DN/20.10.21. You have tried the dimmer on large size head lamps taking a heavy current, each of 12 volt, 48 watt, gas-filled Osram lamps of 100 c.p., taking 4 amperes. We are not surprised that the reduction is too much on such large size lamps, also that the heating would be too great. The switch will have been designed for a more average size of lamp, namely, 24 watt, 50 c.p., and we think you will find, as we find on the bench, that if tried on such lamps as these, both the reduction of the light and the heating are reasonable. It would, of course, be quite easy to get Messrs. Lucas to alter the rating of the switch to suit the large size lamps if required, but I suppose in the first instance Messrs. Lucas have only turned out one rating of switch to be suitable for the average condition. We are putting the dimmer on one of our experimental cars for trial. EFC. | ||