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).
Design changes to an S.S. Sequence Starter's main and auxiliary switch to resolve a motor run-on issue.
| Identifier | WestWitteringFiles\T\November1928\ Scan075 | |
| Date | 7th December 1928 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. E.{Mr Elliott - Chief Engineer} c. Ev.{Ivan Evernden - coachwork} S.S. SEQUENCE STARTER. - MAIN & AUXILIARY SWITCH Unless we revert to the use of the duplex push button switch, such as was desirable in the case of the electrical interlock between the main and auxiliary switches, it is necessary for the teazer or late circuit to be completely broken (carbon contact) by the auxiliary switch before the main heavy current circuit is made by the first contact (carbon). Unless this is so we have a similar recurrence of the old trouble of the motor continuing to run when the push button is released. The particulars given on LeC.2572 do not provide for the breakage of the auxiliary switch before the main switch makes. On the other hand, the breakage of the teazer circuit is .019" late reckoned on the pole centre axis. We have therefore schemed out a set of gaps to satisfy this condition with a reasonable margin, but there results and increased travel kramble of the relay switch and the main switch of approximately .020 and .010 respectively, i.e. main switch travel becomes .060 and relay switch travel .050, the mutual clearance of the lever being about .010". This alteration necessitates more ampere turns on the main switch winding, which we are hoping obtain by increasing the gauge of wire from .028" to .036" dia. We will report further when we have got this switch into satisfactory condition. EFC. | ||