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 report table showing efficiency ratios for a starter motor.
| Identifier | ExFiles\Box 64\1\ scan0307 | |
| Date | 14th June 1928 | |
| STARTER MOTOR TESTS. FORM 5. EFFICIENCY RATIOS. C | ΦE | Φe | ΦS | ΦT | ΦS/ΦE = Ls/E | ΦT/ΦS = Tr{Capt. F. W. Turner - Finance}/Ts | ΦT/ΦE = η | ΦS/Φe --|---|---|---|---|---|---|---|--- 20 | — | — | — | — | — | — | — | — 30 | — | — | — | — | — | — | — | — 40 | 120.0 | — | 104.3 | 19.7 | .870 | .189 | .164 | — 50 | 138.0 | | 113.4 | 47.3 | .822 | .417 | .343 | 60 | 154.8 | | 126.0 | 66.9 | .814 | .531 | .432 | 80 | 191.8 | | 142.0 | 96.4 | .746 | .672 | .501 | 100| 228.5 | | 153.7 | 112.2 | .673 | .729 | .491 | 120| 271.3 | | 164.0 | 128.7 | .605 | .784 | .474 | 140| 326.5 | | 173.9 | 143.5 | .532 | .826 | .440 | 160| 419.0 | | 180.3 | 155.2 | .430 | .861 | .370+ | 180| 554.0 | | 186.0 | 164.0 | .336 | .882 | .296 | 200| 860.0 | | 191.0 | 171.1 | .222 | .896 | .199 | 220| 2305.0| | 194.1 | 177.2 | .0843 | .913 | .0769 | 240| — | | — | — | — | — | — | 14.6.28. | ||