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).
Calculations and design suggestions for the Seagull Dynamo, comparing it to the Goshawk machine.
| Identifier | ExFiles\Box 51\1\ Scan109 | |
| Date | 29th November 1922 | |
| X4383 To R. {Sir Henry Royce} from FFC. c. CJ. c. E. {Mr Elliott - Chief Engineer} c. Ev. {Ivan Evernden - coachwork} EPC4/T29.11.22. X.4010 - SEAGULL DYNAMO. X4383 Herewith please receive calculations in connection with the above dynamo to suit the dimensions given on LsC.1644. The calculations are made principally upon the cutting in point, it being possible to consider a single field winding third brush controlled machine practically as a shunt wound machine at this point. We think the winding detailed, namely, the one of 29 sections of 8 turns per section, giving 464 conductors is more suitable than the other two alternatives given. Generally speaking, we think that this dynamo in proportion to its size as compared with the Goshawk machine will come out considerably better. The whole magnetic circuit seems relatively easier. It has occurred to us, however, that the machine might be slightly improved by allowing a little extra thickness of the carcase, and taking this out of the armature. Undoubtedly the cutting in and output performance of the machine depends upon getting a thoroughly good magnetic circuit and we think that in the both this machine and the Goshawk the number of ampere turns required to drive the flux through the carcase is rather larger in proportion than it should be, our basis for this argument being a comparison of other machines. Again, a slight thickening up of the carcase might enable, by providing increased rigidity, the air gap to be taken smaller. Contd. | ||