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).
Data table detailing performance tests of dynamos for a 20 HP chassis with 57 coil armatures.
| Identifier | ExFiles\Box 165\6\ img211 | |
| Date | 12th October 1929 guessed | |
| X .5660. OF DYNAMOS FOR 20 HP. CHASSIS. (57 COIL ARMATURES PRINCIPALLY). | Cold Controlled | Not controlled Specn. 75°C | Eng. 85°C | Production | |--- |--- |--- |--- | | Ampere peak. | Speed. | Ampere peak. | Speed. | Ampere peak. | Speed. | Ampere peak. | Speed. | | 15.0 | 1375 | 12.0 | 1570 | 11.0 / 9.0 | 1600 / 1550 | 11.0 | 1450 | | 21.3 | 1530 | 18.0 | 1900 | - | - | - | - | | 12.8 | 1360 | 10.4 | 1600 | 9.4 | 1620 | 11.4 | 1450 | | - | - | 11.6 | 1620 | 10.6 | 1640 | 12.5 | 1450 | | 13.5 | 1370 | 11.0 | 1610 | 10.0 | 1625 | 12.0 | 1450 | | - | - | 11.8 / 12.0 | 1520 / 1540 | - | - | - | - | 7° / 9° | - | - | 12.4 / 12.2 | 1750 / 1750 | - | - | - | - | -7° / 9° | - | - | 12.0 | 1700 | - | - | - | - | | ||