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).
Specifications for an armature winding, including materials, dimensions, and testing results.
| Identifier | ExFiles\Box 37\2\ scan 092 | |
| Date | 19th July 1917 | |
| R.R. 199 (2SGT) (SD676 19-7-17) MP 18086 Contd. -2- The wire used is single silk covered, .033" in dia. (21 S.W.G.) and the winding, of a 4 pole, right hand wound, progressive wave type, only it has no end connections in the front. The pitch in slots is 5 (1 to 6). Tape, impregnated with shellac, .014" thick was used to bind them up with. There were 136 stampings, .019" thick, insulated from each other by a thin layer of oxide of iron and dirt, which, in an armature core of 2.5" gives an efficiency of .98. At each end is an insulating stamping of pressed paper, or cardboard, .073" thick, the whole being clamped between a flange and a 7/8" nut running on the shaft. The slots were insulated with a stiff grey brown paper, .015" thick, with block tape .062" thick on the shaft under the end connections. The resistance was .4 ohms at 22°C, taken between com. bars, 1 and 5, and 1 and 6. In testing for advance or retard of brushes, the poles of the armature came midway between the contact points feeding the current in and out, of the armature, which, as the machine was a 4 pole one, were 4 in number. This coincided with the makers setting; The brushes were located immediately under the pole pieces. COMMUTATOR AND BRUSHES. Length of com -- .6" from riser, or .75" overall. Dia. of com. = 1.254 inches. | ||