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).
Explaining the new output curves for the Phantom II 45 Coil Dynamos.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan127 | |
| Date | 9th January 1931 | |
| To R.{Sir Henry Royce} from EFC. c. Sg.{Arthur F. Sidgreaves - MD} c. E.{Mr Elliott - Chief Engineer} By.{R.W. Bailey - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} PN.{Mr Northey} X.6004. X.6006. PHANTOM II 45 COIL DYNAMOS OF MEDIUM AND HIGH OUTPUT. We attach two blue print sets of curves for 40/50 dynamo output labelled 1 and 2. Unlike previous curves issued, all dynamo output curves, unless otherwise specifically stated, will now be for a constant operating terminal voltage of 14.0 at the same time as the temperature of 80°C. is indicated on the carcase in our usual way. We would like it to be clear that the dynamo carcase temperature is definitely held at 80°C. for the purpose of these curves and would wander away from it, either increasing or decreasing, if steps were not taken to keep that temperature constant. The setting of the brushes both main and control is on a definite temperature rise basis with the dynamo working on its peak of output. Therefore, output curves can be raised and lowered (by varying the control brush) by varying the allowed temperature rise. When the dynamo is on the car the output indicated may be considerably different from the curves for the reasons that (a) The operating voltage may be different according to the state of battery charge, temperature of battery, and the amount of load. (b) The temperature of the dynamo may be different. If the battery and dynamo are cold and the battery in a fully charged condition, the output will be considerably greater than the curves show. In general the output will be greater than the curves show, but it may happen in an extreme case of dynamo and battery temperature and of low battery P.D. (owing possibly to load exceeding dynamo output) that the output is a little less. | ||