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).
Page describing the electrical behavior of primary and secondary currents and flux redistribution in an armature core.
| Identifier | ExFiles\Box 4\5\ 05-page086 | |
| Date | 10th April 1929 | |
| -17- Contd. armature core due to current in the windings, takes, at this instant, the place of that primary current. The primary current itself has, as already stated, become zero after a few quick oscillations. The secondary current, however, not only consists of the quick oscillations, but also of this unidirectional component which is immediately instituted at the instant of breakdown of secondary gap and thereafter proceeds to die away at a rate determined by the inductance and resistance of the secondary winding. The armature flux held by this current in the secondary winding, also dies away concurrently with the current, but both at a rate which is comparatively slow compared with even the first oscillations which we have considered. At the same time, the further rotation of the secondary winding in the field due to the permanent magnets, prolongs this arc discharge more than would otherwise be the case. Thus in one's mind it is necessary to consider the redistribution of flux in the armature core following on the point of break to take place in two stages. During the first stage the redistribution is taking place relatively quickly until sufficient voltage is put up on the secondary to break down the secondary gap. Subsequently the further redistribution takes place more slowly and concurrently with the arc discharge. It will readily be understood that if the high tension gap is easily overcome, the first portion of the flux redistribution is a relatively small portion, the amplitude Contd. | ||