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).
Technical memo discussing the performance and potential modifications for a Rotax dynamo.
| Identifier | WestWitteringFiles\F\March1921\ Scan56 | |
| Date | 30th March 1921 | |
| R.R. 885A (100 T) (S.H. 798. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 ORIGINAL To R.{Sir Henry Royce} from EFC. c. to CJ. EFC1/T30.3.21. X.1005 - ROTAX DYNAMO. We have your note R3/G24.3.21 The effect in the Rotax dynamo of inserting resistance in the field circuit was not quite as we anticipated. Owing to the fact that in normal operation the magnetic circuit is approaching saturation at about the cutting-in speed of the machine, it requires the insertion of considerable resistance (about equal to that of the field winding) to increase the balancing speed from 400 to 500. This caused the peak output to be unduly reduced. We do not find, therefore, that we can do much in this way towards altering the curve to be nearer to that of the specified performance, but we are at present taking a curve with a small resistance in the field circuit for comparison. It would appear that what is necessary is about 20% fewer conductors on the armature, but this again would probably reduce the peak and increase the heating for the same brush setting. The Rotax dynamo so far as we can tell on the bench is the most silent of any dynamos we have had. There is, however, a slight ball bearing rattle at high speeds. We have already carefully confirmed the number of segments in the commutator and our previous figure of 28 segments is quite correct. We cannot, however, say how it is wound. Cont.d | ||