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).
Test results for a Watford EW.6 Magneto, showing short circuit current at various speeds.
| Identifier | ExFiles\Box 65\3\ scan0383 | |
| Date | 19th July 1929 | |
| X7791 19.7.29. WATFORD EW.6 MAGNETO NO.99802. Speed Short circuit amperes. % of that at 3200 r.p.m. 100 .58 20.8 200 1.15 41.3 300 1.65 59.3 400 1.93 69.5 600 2.20 79.2 800 2.35 84.5 1200 2.52 90.7 1600 2.63 94.6 2000 2.70 97.2 2400 2.75 99.0 2800 2.77 99.7 3200 2.78 100.0 EFC. | ||