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).
Analysis of the compound windings on the regulator side of the cut-out and their effect on dynamo speed and current delivery.
| Identifier | WestWitteringFiles\F\February1921\ Scan70 | |
| Date | 2nd February 1921 guessed | |
| Contd. -3- EFC1/T2.2.21. diagram of connections will show that the compound windings on the regulator side of the cut-out consist of (1) The usual compound winding carrying the main current delivered by the dynamo in an additive direction magnetically. (2) A winding carrying the main field current of the dynamo, also in an additive direction magnetically. One can readily appreciate the functions of the first winding as being the function of any compound winding on vibrator regulator control, e.g. to limit the rush of current when the battery is low in voltage. The function of the other winding we have not been able to appreciate. Such a winding introduces a speed effect. As the dynamo is driven faster, the field current for a given voltage is necessarily smaller, this being regulated by the contacts. Hence the main voltage must rise in order to produce additional ampere turns on the shunt coil, to compensate for this. There will follow as a consequence of this, the fact that the current delivered to the battery in a given condition will be greater at higher speeds than at lower speeds within the regulating range. The ordinary compounding coil on the other hand cannot have such a speed effect. We have taken an open circuit volt speed curve of the dynamo and regulator, together with associated field current speed curve for two conditions, one in which this main field current regulator coil was included in the circuit as on the diagram, the other in which the connection was altered so that the field current did not have to traverse this coil in passing Contd. | ||