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 suitability of a 'REX' headlight controller with various lamp configurations.
| Identifier | WestWitteringFiles\F\April1921\ Scan102 | |
| Date | 15th April 1921 | |
| R.R. 235A (50 T) (S.H. 986. 10-2-21) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 8008 95211. EFC. 15.4.21. X.4344 - "REX" HEADLIGHT CONTROLLER. The total resistance of this controller is 9.4 ohms. It is suitable for a single O.M.F. lamp taking 2.0 amperes at 12 volts (actually two side lamps in parallel) and on such a lamp gives a suitable range of brilliancy adjustment. On a single half-watt type lamp which normally takes 2.0 amps, the resistance is a little two high as the filament only just glows with all resistance in, the current then being 1.0 amp. With two such lamps in parallel no light at all is obtained until the lever is half way over when the current is 2.45 amps (1.225 amps. each lamp) and the lamps are a bright cherry red, but not as bright as if in series on 12 volts. On O.M.F. lamps taking 2.5 amps. each, when in parallel the lamps glow earlier in the adjustment than in the previous case, but total resistance of controller appears too high. An amount of light equivalent to that obtained with lamps in series on 12 volts is obtained with the lever only 50% down its range from full brilliancy. EFC. | ||