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).
Block diagram of a non-earthed electrical system.
| Identifier | Morton\M2.3\ img009 | |
| Date | 28th September 1921 | |
| 3 Non-earthed R.R. switchbox and Ammeter. Lights. Small new distribution board. JUNCTION X.4169 Smith cutout Dynamo. D Lucas Junction Box. Various circuits. Battery Motor. R.R. 2954 (100 T) 28.9.21 G.89 | ||