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).
Graph showing top gear dynamo output in amps versus speed in miles per hour under different lighting loads.
| Identifier | ExFiles\Box 62\3\ scan0033 | |
| Date | 25th February 1930 | |
| TOP GEAR DYNAMO OUTPUT. DYNAMO. N. WITH 4S COIL ARMATURE AND TRAILING FIELD POLE MODIFICATION MILES PER HOUR AMPS WITH HEAD LIGHTS SIDE, TAIL, AND FACIA BOARD LIGHTS DYNAMO OUTPUT WITH NO LIGHTS ON 20/25 HP 5.25 COMPN 9/41 HYPOID 1464 25-2-30 YHH | ||