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).
List of winding wires used on auto charge control and green lamp switches for 12 volt and 6 volt systems.
| Identifier | ExFiles\Box 60\3\ Scan028 | |
| Date | 22th February 1928 guessed | |
| X4040 WINDING WIRES USED ON AUTO CHARGE CONTROL AND GREEN LAMP SWITCHES X.4008 X.4040 12 volt { R.R. Volt coil Copper 32 SWG. D.S.C. Eureka 23 SWG. D.C.C. R.R. field coil Eureka 30 SWG. D.C.C. } 6 volt { U.S.A. volt coil. Copper 28 SWG. D.S.C. Eureka 20 SWG. D.C.C. U.S.A. Field coil Eureka 26 SWG. D.C.C. } | ||