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 current measurements and calculations for a Lucas E.575 Dynamo.
| Identifier | WestWitteringFiles\D\February1920\ Scan11 | |
| Date | 7th February 1920 guessed | |
| X. 294 - LUCAS E.575 DYNAMO X. 3034. Table of currents (Handwritten note for the last three columns: brush currents) Speed. | Main current (M) | Field current (F) | Control current (C) | Main + ve brush current (M + F) | Main - ve brush current (M + F - C) --- | --- | --- | --- | --- | --- 725 | 0 | 1.9 | -7.1 | 1.9 | 9.0 1000 | 5.85 | 2.1 | -1.25 | 7.95 | 9.2 1250 | 9.4 | 2.2 | 4.25 | 11.6 | 7.35 1500 | 11.4 | 2.2 | 8.7 | 13.6 | 4.9 1750 | 12.2 | 2.2 | 11.8 | 14.4 | 2.6 2000 | 12.5 | 2.2 | 13.6 | 14.7 | 1.1 2200 | 12.5 | 2.2 | 14.6 | 14.7 | .1 2250 | 12.5 | 2.2 | 15.0 | 14.7 | -.3 2500 | 12.5 | 2.15 | 15.7 | 14.65 | -1.05 2750 | 12.4 | 2.15 | 16.3 | 14.55 | -1.75 3000 | 12.3 | 2.1 | 16.7 | 14.4 | -2.3 3250 | 12.1 | 2.1 | 17.0 | 14.2 | -2.8 3500 | 12.0 | 2.1 | 17.3 | 14.1 | -3.2 [Handwritten Diagram and Formulas] Around a diagram of a dynamo armature and brushes: A + 2/9C C M+F M+F+C A - 7/9C A - 2/9C 1/2(M + F) = A Maximum current 17.3 amperes. Brush area 2 x .625 x .300 = .375 sq." Amperes per square inch (max) 46.1 | ||