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).
Output speed performance curves of a 48 coil dynamo modified in various ways.
| Identifier | ExFiles\Box 62\3\ scan0138 | |
| Date | 27th January 1931 | |
| X.6004. To R.{Sir Henry Royce} from EFC. C. SG.{Arthur F. Sidgreaves - MD} C. WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} C. Ey. FN. EFC4/AD27.1.31. X.6028 X.6008 X.6004. OUTPUT SPEED PERFORMANCE CURVES OF 48 COIL DYNAMO MODIFIED IN VARIOUS WAYS. Attached please find a blue print set of output speed curves taken on a 48 coil F.2. dynamo (S.S.X.) in various conditions. The data for this set of curves was taken before the end of last year and therefore this set is not included in our numbering scheme neither are the curves 14.0 volt curves like the new ones. The operating voltages are, as in the case of other old curves, to our schedule operating voltages as given on the blue print. The curves are, notwithstanding this, of a relatively comparative nature. They represent an investigation into the relative value of (a) Finer field winding. and (b) Increased concentric air gap. are compared, the curves being as follows:- I. For the machine in normal condition. II. For the machine with finer gauge field winding only. III. For the machine with increased concentric air gap only. IV. For the machine with both the finer field winding and the increased concentric air gap. On inspection of the curves, which are all on the basis of the same temperature rise, it will, we think, be agreed that No.III for the machine with increased concentric air gap and normal field winding is the best generally. The effect of the finer field winding in each case has seemed to be an increase in the cutting in and a later, though practically equal, peak output (e.g. compare II with I and IV with III) whereas the effect of increased concentric air gap is to affect the cutting in to a lesser extent than in the other case and at the same time to increase the peak and subsequent output (e.g. compare III with I and IV with II). | ||