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).
Dynamo armature types, their outputs, modifications, and charging schemes for the 20/25 HP model.
| Identifier | ExFiles\Box 163\6\ img042 | |
| Date | 16th May 1930 guessed | |
| -2- in the 20/25 HP. case). This type of armature normally allows the dynamo to give an output intermediate between that given by the present standard 56 coil normal output armature and the higher output 56 coil armature, which output we call "medium output". Modification of the dynamo pole pieces modifies this output so that it becomes almost exactly similar to that of the higher output 56 coil armature without polar modification. We then call the dynamo the high output 48 coil armature dynamo. With the reduced charge switching scheme, there has been agreed to be every reason for maintaining the height of the output speed curve at speed, but we are still of the opinion that in the absence of such a scheme it would not do to use the high output, except in special cases, because it is definitely bad for the battery. The medium output 48 coil armature machine without polar modification is representative of the up-to-date compromise with the size and drive speed of the machine we can use, and with the now available improvements in batteries would be reasonably suitable without the half charge scheme. Mr. Elliott's proposal of putting resistance in the dynamo positive brush wire appeared on principle, to be likely to give a somewhat better cutting in result on reduced charge even without much increasing the watts to be dissipated in the resistance. It was found however, | ||