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).
Report page detailing the voltage and current characteristics of a dynamo connected to a battery.
| Identifier | WestWitteringFiles\C\May1919\ Scan48 | |
| Date | 7th May 1919 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. -5- EFC1/T7.5.19. Contd. secondly when correctly connected according to diagram (c) on sheet F.{Mr Friese} This voltage is somewhat higher when correctly connected, owing to the additional magnetisation due to the control winding. The voltage attains a value of 12.4 at a speed of 680 R.P.M. and a value of 13.6 at a speed of 725 R.P.M. These two particular voltages are given for the reason that the first represents the voltage of a battery after standing and when practically fully charged, the second represents the voltage of a battery which has been gassing up on charge. These should be compared with figures given for the cold condition above. They are, unfortunately, somewhat higher than similar figures for the C. A.{Mr Adams} V.{VIENNA} dynamo, e.g. 580 and 600 R.P.M. Thus, the voltage will rise considerable if not controlled by a battery. Curves C show the current speed characteristics of the machine when connected as a simple shunt wound dynamo. Curves D show the out-put speed curves when the machine is correctly connected to 4,5,6, and 7, fully charged large capacity cells in series. There are also plotted on this sheet the field currents and the control currents. The want of regularity in the components of this series of curves and in the series on sheet C may be due in part to the temperature of the field windings being slightly different in the two cases, and also in part, to the voltages of the batteries used being somewhat out of proportion to the number of cells, the general result, however, is not affected. It will be seen that here again we have the characteristic that the greater the opposing voltage, the greater the current delivered (at normal running speeds). The control current in each case starts negatively (we are considering the control current to be positive | ||