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).
Fault where the green lamp on the S.S. Distribution Board fails to switch off due to an overlooked circuit path.
| Identifier | ExFiles\Box 65\2\ scan0157 | |
| Date | 13th December 1928 | |
| X7740 To R.{Sir Henry Royce} from EFC. c. BJ. BY.{R.W. Bailey - Chief Engineer} EFC4/T3.12.28. S.S. DISTRIBUTION BOARD GREEN LAMP SWITCH. X4060 We have arrived at a point in connection with the above that has previously been overlooked, viz. that as a result of not breaking armature connection (dynamo +ve brush) to battery in M & B or first position of switch, green lamp may remain on when charge is put off by switching to M & B, the current for its coil being supplied by the battery via +ve brush, armature, control brush field winding to terminal C on distribution board. Thus green lamp will often not go off when charge is switched off. The reason it will go off sometimes is that the inductive action of the stoppage of the field current temporarily lowers the voltage (to earth) available at terminal C from which the green lamp operating coil is supplied. EFC. | ||