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).
The 'Liberty' shunt wound dynamo, including weights and circuit specifications.
| Identifier | ExFiles\Box 37\2\ scan 100 | |
| Date | 7th August 1920 | |
| EFC. P.A.7. 91158 August, 7th, 1920. X.3306. - DETAILS OF "LIBERTY" SHUNT WOUND DYNAMO. WEIGHTS. Complete machine with pulley, but without suspension. 11 lbs. 11 ozs. Armature complete without pulley 3 lbs. Bore weight of carcase and pole pieces = 4 lbs. Armature stampings. 1 lb. 7 ozs. Armature copper (without insulation) 8 ozs. Field copper (without insulation) 1 lb.1 oz. AIR GAP. Single .013", FIELD CIRCUIT. Resistance = 4.06 ohms at 20°C. It consists of 4 coils connected in series, on solid pole pieces, each coil having 145 turns of single silk covered wire .032" dia. (approx. 21 S.W.G.) which were waxed, and then bound up with tape impregnated with shellac, to a thickness of .048". ARMATURE CIRCUIT. This armature has 21 slots, 21 com. bars, and 11 turns per coil which gives, 21 coils, 1 coil per slot, 462 conductors, 22 conductors per slot and 42 virtual conductors. Contd. | ||