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).
The performance and heating issues of an instrument board dimmer switch.
| Identifier | ExFiles\Box 168a\1\ img058 | |
| Date | 7th December 1936 | |
| 6135 To E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Wst. c. to Sg.{Arthur F. Sidgreaves - MD} c. to Hs.{Lord Ernest Hives - Chair} c. to By.{R.W. Bailey - Chief Engineer} Rm{William Robotham - Chief Engineer}/Wst.5/AP.7.12.36. INSTRUMENT BOARD DIMMER SWITCH. Replying to your E.3/HP.1.12.36., the new dimmer units to RR.Sch.1007 are well in hand and we hope to have these on test shortly. With regard to the original switch reported under cover of Rm{William Robotham - Chief Engineer}/Wst.3/JH.18.11.36., we have rewound the same with coarser wire and find that owing to the turns of wire being packed closer together the heating of the unit is unaltered i.e. the expected reduction in heating due to increase in the gauge of the wire is not realised due to less heat conduction or radiation from the turns. To obtain a heat reduction the unit must be made longer to obtain the original spacing between the turns. The dimming effect was also less due to the resistance of the new winding being only 6.15 ohms as compared with 8.63 ohms originally. Rm{William Robotham - Chief Engineer}/Wst. | ||