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).
Wiring diagram for a relay switch used for battery charge control, connected to a green indicator lamp.
| Identifier | ExFiles\Box 60\3\ Scan054 | |
| Date | 28th March 1928 | |
| X4040 THROUGH GREEN LAMP TO EARTH RESISTANCE FINISH COPPER FINISH N SUPPLY FROM AMMETER SIDE OF MAIN BATTERY FUSE FROM DIS. BOX TERMINAL B. TO EARTH CONNECTIONS OF RR GREEN LAMP RELAY SWITCH FOR BATTERY CHARGE CONTROL 28/3/28 H.W.m. C | ||