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 performance limitations and a proposed experiment for a new armature winding.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan212 | |
| Date | 6th May 1928 | |
| -2- To R.{Sir Henry Royce} from EFC. (Contd) EFC3/127.2.28. lamps. A dynamo of our present size which would be capable of covering such a night load at high speeds would be entirely unsuitable for the average car. Even if it could be arranged to have the same cutting-in point it would give far too much overcharging at other times (unless an auto charge control switch were provided) but it is extremely improbable that a dynamo of the present size could be capable of giving this output without overheating at the higher speeds if it were made to cut in at the early speed of our present machine. The only possible course would appear to be to supply a special type of dynamo with a different winding giving later cut-in for this particular type of customer. As a preliminary and simple experiment, we are having an armature wound with the coils paralleled to half the virtual number of conductors and capable, therefore, if necessary, of giving twice the current for the same heating. The cutting-in of this dynamo will be at nearly (not quite) twice the speed; the rise of current will be, we think, approximately at the same rate as at present, and the peak of current before control begins will be considerably higher and at higher speeds. In fact, without altering anything else, such an armature might meet the case. It is possible that this course will go further in the required direction than we want to go for the purpose, but it is a simple thing to test in the first instance to enable us to arrive at a suitable extent to which to reduce the number of armature conductors and increase the output capacity of the armature accordingly. EFC. | ||