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 2 of a report detailing the performance and physical specifications of an electrical machine.
| Identifier | ExFiles\Box 180\M1\7\ img009 | |
| Date | 28th September 1921 | |
| R.R. 285A (100 T) S.H. 798. 10-12-20 G 2547 Contd. -2- EFC1/T28.9.21. comply with this condition we found to be 14. In the cold condition a voltage of 6.2 was attained at a speed of 365 r.p.m. In the fully hot condition a voltage of 6.8 was attained at a speed of 430 r.p.m. These are comparatively early cutting-in speeds, but the rise of output after the cutting-in point was not very rapid in the hot condition. The carcase dia. is 5.5", length 4.5", thickness 3.13". The armature dia. is 3.5" and active length 2.875". Armature conductor overhang at .875" driving end. Length of comm. connections 1.40" (excluding comm. spokes) Ditto (including comm. spokes) 1.575" Weight of the machine is 24.5 lbs. (including cutout). Weight of armature complete, without 8.3 lbs. pulley. Air gap .029" Field resistance 1.64 ohms at 16°C. No. of slots 21. No. of coils or comm. bars 43. Armature resistance .235 ohm at 18°C. Commutator dia. 2.15" Useful length 1.05" (to R + Da{Bernard Day - Chassis Design}) We attach a sketch showing certain other particulars of the magnetic circuit. EFC. | ||