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 a Lucas Head Light Dimmer, detailing issues with switch travel and excessive heat generation.
| Identifier | ExFiles\Box 61a\1\ scan0125 | |
| Date | 20th October 1921 | |
| X4291 Bk{A. Birkett - Commercial Manager}14/DN/20.10.21. S/W. X.4291 EFC. Re Lucas Head Light Dimmer. We have tried this switch on 81-TW having 12V48W gas filled Osramlamps and on 2-LW, having BTH ½ Watt lamps. In each case we found that quite a small travel on the switch road was sufficient to reduce the lights from full on to dim. With the switch fully out, the lights on 81-TW were cut down to nothing and the resistance wire became very hot. The same thing happened on 2-LW, but in a lesser degree. We feel that the resistance wires should be arranged so that it takes the full travel to reduce the lights from full on to a safe driving light, as when on the road one cannot adjust this switch to a nicety in the time available. Also with the switch in the position where the lights are reduced to nothing, we are rather concerned with the excessive heat which is generated. We agree that the design and workmanship of the switch is quite good. Bk.{A. Birkett - Commercial Manager} | ||