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).
Technical specifications and performance data for a 12-volt combined starter and lighter system.
| Identifier | ExFiles\Box 48\3\ Scan317 | |
| Date | 10th January 1921 guessed | |
| X4216 Combined Starter & Lighter, 12 Volts System. To Starter Locked Torque on pinion 67.5 ft lbs. 0.68 H.P. when running at 180 r.p.m. on pinion; geared 1.70 to 1 to pilot shaft on 12/20 B.A.C Car. = 106 r.p.m. of Engine 0.60 " " " " 220- " " " " " " " " " = 129 " " " 0.50 " " " " 245- " " " " " " " " " = 144 " " " 0.40 " " " " 300- " " " " " " " " " = 176 " " " As Dynamo; output controlled by "Third Brush" Commences to charge 12 Volt Battery at 800 r.p.m. (this can be reduced to 600 r.p.m.) Gives 10 Amperes at 1200 to 1600 r.p.m. " 8 " " 4000 to 5000 - - - The Armature on Starter revolves 3 times as fast as its pinion " " Dynamo revolves at same speed as its pinion The change of gear is silent, and perfectly automatic, and has never failed to change during all its severe testing A | ||