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 two types of electric cables, numbers 254 and 255.
| Identifier | ExFiles\Box 168b\2\ img113 | |
| Date | 14th September 1923 | |
| Revised 14.9.23. SPECIFICATION NUMBER 254. MATERIAL. Electric cable. 600 megohm grade. TYPE OF CORE. Twin. CORE SIZE. 2-90/36. OUTSIDE DIA. .422 Maximum. CONDUCTOR. High Conductivity Tinned Copper Wire. DIELECTRIC. One layer pure and two layers vulcanizing rubber. The radial thickness of the pure rubber shall be at least .006 and the total thickness of the dielectric must be .035 minimum. PROTECTIVE COVERING. Each core taped. One core coloured red and the other white. Cores twisted together and wormed circular with cotton. Taped and protected overall with a Ferflex braid of 36 S.W.G., tinned copper wire. SPECIFICATION NUMBER 255. MATERIAL. Electric cable. 600 megohm grade. TYPE OF CORE. 3 Core. CORE SIZE. 2-90/36 1-70/36. OUTSIDE DIAMETER. .460" Maximum. CONDUCTOR. High Conductivity Tinned Copper Wire. DIELECTRIC. One layer of pure rubber and two layers of vulcanising rubber. The radial thickness of the pure rubber shall be at least .006 and the total radial thickness of the dielectric must be .035 minimum. PROTECTIVE COVERING. Each core taped 1 - 90/36 coloured red, and the other white; the 70/36 coloured black. Cores twisted together and wormed circular with cotton. Taped and protected overall with a Ferflex braid of 36 S.W.G., tinned copper wire. | ||