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).
Page of calculations for engine speed, torque, and electrical resistance.
| Identifier | ExFiles\Box 64\2\ scan0165 | |
| Date | 30th June 1928 guessed | |
| -2- Contd. If Z = 90, Ø = 197,000 Engine speed = 640/16 = 40 r.p.m. Engine torque = .90 x .85 x 16 x 90 = 1100 lb-inches. By the usual tabular calculation the field ampere turns for Ø = 197,000 may be anything from 180 x 3½ to 180 x 6½ . Total ohmic resistance = 4.60/180 = .0255 Armature resistance for 90 conductors as arranged = .014 ohm. For brushes etc. allow = .004 ohm. For field we have only allowable .0075 ohm. 3½ turns winding gave .0038 ohm. EFC. | ||