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).
The required resistance to reduce voltage for instrument lamps in a Ph.XII arrangement.
| Identifier | ExFiles\Box 168a\1\ img078 | |
| Date | 29th April 1937 | |
| By/AD. from Wst/KC. 6135 Wst/KC.9/AP.29.4.37 In connection with the Ph.XII. arrangement of instruments to M.R.Scheme 1011, and the arrangement of 3.5 volt lamps to M.R.Sch. 1041, the current taken by the six lamps was found to be .61 amps at 10.5 volts. In order to reduce the voltage from 15 to 10.5 a resistance of 7.5 ohms, capable of carrying a current of .61 amperes will be required. Wst/Rc.{R. Childs} | ||