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).
Table of electrical measurements and running quantities for a standard ignition system.
| Identifier | ExFiles\Box 54\5\ Scan283 | |
| Date | 25th March 1925 | |
| X3485' 25.3.25. RUNNING QUANTITIES OF STANDARD IGNITION SYSTEM. X8680 X3485' Representative Observed Observed figures (8 volt). figures (8 volt) figures (12 volt). (.5 make ratio). (.55 make ratio) PRIMARY Resistance (cold). .90 .87 .87 Res. (working condition). 1.18 .96 1.03 Inductance (henry). .0096 .0096 .0096 BALLAST Res. (cold). .84 ..86 .86 Res. (working). 1.35 1.08 1.68 R.M.S. current. 1.34 1.20 1.74 Av. current. .87 .865 1.255 Potl. difference (average).1.17 .935 2.11 Dissipation (watts). 2.42 1.56 5.08 PRIMARY & BALLAST Res. (cold). 1.74 1.73 1.73 Res. (working). 2.53 2.04 2.71 Sh. circt. current. 1.84 2.16 2.44 CONTACT BREAKER Make ratio .5 .5 .55 Current at break. 2.68 3.06 3.95 (calcd). EFC. {E. Fowler Clarke - Electrical Engineer} | ||