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).
Proposed arrangements and issues with reduced charge switching circuitry.
| Identifier | ExFiles\Box 163\6\ img011 | |
| Date | 30th January 1930 | |
| X6016 To E.{Mr Elliott - Chief Engineer} from EFC. c. Sg.{Arthur F. Sidgreaves - MD} c. By.{R.W. Bailey - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} EFC1/AD30.1.30. 6016 X.7730. REDUCED CHARGE SWITCHING. Your E2/M25.1.30. X7738 X7740. If the extended armature contact is provided as recommended, then when the lamp switch is on "head" and the charge switch on "M & B", full output of the dynamo will be realised, because then both dynamo field and armature positives will be connected to battery positive and not the field alone as referred to in your 3rd paragraph. The fact that this position of the charge switch is not labelled "charge" is consistent with the fact that there will be little actual charge in those circumstances, owing to the head lamp load. This would appear to be a desirable combination of circumstances. But there is however, another "catch" in the proposed arrangement in that it becomes impossible X to retain the connection of the positive end of the cut-out shunt coil to the dynamo field positive at the distribution box. The available voltage at this point when the dynamo field resistance is in circuit will be reduced and the cut-out operation interfered with. Apparently you appreciate this point, because on your blue print diagram you shew the positive end of the cut-out shunt connected to the dynamo armature positive. This however, though not impossible, is very undesirable. You will remember that some while ago we standardised the positive connection of the cut-out shunt coil to dynamo field positive for certain very good reasons, connected with the possibility of overheating the cut-out shunt coil in circumstances described at the time. Our recommendation therefore, will not include returning to that old feature of the system. The only satisfactory way which we can see out of the difficulty is also to provide a further terminal (2R) on the distribution board for the cut-out positive. The development of the idea is illustrated by figures 1, 2, 3 and 4 in which the top of each represents terminals on the switchbox and the bottom, terminals on * i.e. without further modification. | ||