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).
Modifications and observations of the S.S. sequence starter system.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan257 | |
| Date | 4th June 1929 | |
| ORIGINAL R.{Sir Henry Royce} from EFC. c. SG.{Arthur F. Sidgreaves - MD} c. Ev.{Ivan Evernden - coachwork} c. E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} Wor.{Arthur Wormald - General Works Manager} EFC2/AD4.6.29. X.7655. S.S. STARTER SYSTEM. X.7625 We have now, in adopting the latest approved modifications of the S.S. sequence starter motor system on one or two recently modified S.S. chassis, arrived at a condition of that system which, we think, is reasonably right. The principle modification referred to is the .075 increased armature travel. Careful observations of the operation have been made on the two chassis, 19-EX and 23-EX, first to be so fitted. It will be remembered that one of the modifications instructed was a longer spring (called Z), which we designed with considerably more turns and lower rate than previously. In making the observations above referred to, we were inclined to conclude that this very low rate spring had somewhat overshot the best main spring arrangement. whilst exerting suitable forces in the initial and just engaging position of the armature travel, it appeared to us to store a smaller quantity of potential energy than was desired. The result of this appeared to be slightly evident in two ways (1) A tendency to thump on engagement (damper as previously arranged to cut out thump on engagement with higher rate spring). (2) The time for the motor armature to get out of contd. | ||