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).
Analysis of a starter motor fault involving pinched brush flexibles and comparison of switch designs.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan247 | |
| Date | 27th May 1929 | |
| -2- EFC5/D27.5.29 contd. Apart from the fact that the base of this switch would now be a bakelite moulding, it will be remembered that this design of switch has been temporarily replaced by the older type of design which has given very satisfactory experimental service. (3) As a result of subsequent removal and replacement of the starter motor end cover, one of the brush flexibles (on the live side of the armature electrically) became pinched (and consequently earthed) between the cover and the spigot, this causing the main armature current to be diverted to earth, in which case the motor would still attempt to engage but without rotation, circumstances which would permit of the pinion being badly chewed up by the wheel, as was observed to be the case. Also it is the case that the relative heating evidences in the various coils, and the burning effects on the various contacts, where such existed, are in accordance with the above diagnosis. For the above faults to be repeated on further systems, several of which we have now going satisfactorily, is wholly improbable. In fact we have had another system, not quite similar, but with ebonite insulation, which has run 17,000 miles in France without failure. EFC. | ||