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 resistance bobbin, including calculations for volts, amperes, and a table of machine speed versus scale readings.
| Identifier | ExFiles\Box 34\2\ Scan052 | |
| Date | 6th November 1918 | |
| RR 238 (300 Bks.) (SF 152. 6-11-18.) MP 197880 ROLLS-ROYCE LIMITED. INSTRUCTIONS. 19 To Order No Customer's No. 4 resistance bobbin, totals 571.9w. Hence with the resistance in series with the instrument, the scale reading per volt is #248.25 and the full scale volts are 8.05; the corresponding ampères being .00175 and .0141. The scale proportionality is very good throughout. When connected to the instrument in series with the resistance, the speed of the machine bears an increasing proportion to the scale reading, as below. Reading | Speed | Ratio 500 | 1070 | 2.14 700 | 1525 | 2.18 1000 | 2250 | 2.25 1500 | 3550 | 2.365 2000 | 4880 | 2.44 Signed F.J. Allen. This Sheet must be filed on completion of the work. | ||