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).
Improving dynamo performance through modifications to brush holders and air gap adjustments.
| Identifier | WestWitteringFiles\M\2April1925-June1925\ Scan67 | |
| Date | 9th May 1925 | |
| Contd. -3- EFC4/T9.5.25. brush holders for the main brushes and the EAC. type of 20 HP. control brush holder for the control brush; or some arrangement similar thereto, by which we reduce the circumferential width of all the brushes to about 2/3. We think we may come to a point where we shall definitely recommend this. Another item upon which we are working is to make the output curve keep up a bit better at high speeds, and in this connection we have made some experiments with an exaggeratedly increased air gap of .025" (.015" being standard). This reduces the armature reaction and makes the control less effective, but unfortunately, of course, has an effect on the cutting in. Since on these new EAC. chassis we can probably think of the average speed as being higher, and at the same time as we have at present a bit in hand on the cutting in (even on our specification figure which is already quite low) it is probable that we can easily allow a loss of cutting in which we should get with an air gap of say .020" in place of .015"., and we think that here again we may come to the point of recommending this air gap as standard. These are merely some preliminary remarks on our investigations for improving the EAC. dynamo to the last ounce. Contd. 4 | ||