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 mechanical disengagement issue, discussing energy absorption, gear noise, and the necessity of a fluid friction damper.
| Identifier | WestWitteringFiles\T\November1928\ Scan082 | |
| Date | 11th February 1928 guessed | |
| -4- Contd. in this new case. It appears that the thump on disengagement is a mechanical problem independent of the electrical functioning of the system. Assuming that we wish to get the armature pinion clear of the wheel within a certain time after the engine first fires, that means a certain longitudinal velocity and implies a certain mechanical energy in the armature which/has to be absorbed. It does not appear to concern us very much whether the get-out is done entirely by main spring or partly by spring and partly by helical teeth. The problem of absorbing the energy would appear to be the same. If we say we do not want to get the armature out quickly then we have rather more prolonged gear noise and a fast spinning motor after disengagement, which also makes a noise. It would appear that some kind of fluid friction damper is absolutely essential. As stated, from the point of view of certainty of functioning, apart from objectionable noises, the arrangement tested yesterday afternoon on the test bed engine is undoubtedly the nearest approach to reliability which we have had. The said engine has now been put on 18-EX chassis and we are changing over the switch unit correspondingly, so that this equipment will now be on that chassis for further test. It should have been stated that the switch, although of somewhat increased main switch lever travel, pulled down completely on 8 volts on the main switch coil winding operating both main and relay switch lever, without the assistance of the relay switch magnetising coil. EFC. | ||