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).
Testing and potential modifications for a Green Lamp Switch, focusing on armature and field contact breaks.
| Identifier | WestWitteringFiles\T\November1928\ Scan076 | |
| Date | 12th December 1928 | |
| To R.{Sir Henry Royce} from KFC. c. BJ. BY.{R.W. Bailey - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} ORIGINAL EFC4/112.12.28. X4040/7740 GREEN LAMP SWITCH. again Further to our EFC3/T12.12.28, it is probable that a failing neck voltage of 12.0 would meet the case on account of the assistance of the depression of the voltage at terminal C on the distribution board at the time of switching off, rendered by the tendency of the field current to continue its passage through the windings. The only alternative would appear to be to revert to the condition of breaking the armature contact in the first position of the switch (M & B or I as the case may be) but so arrange this armature contact as to break as late as possible in relation to the field break when the switch is moved to this position from the charging position. We have in progress a systematic series of switchboard contact burning tests in different circumstances in which we operate the switch on and off by mechanical means for many thousands of times, the dynamo being meanwhile driven at constant speed (peak output). We could include in this series of tests different degrees of delay of the armature break in relation to the field break. In our first test of this series, there was such a moderate delay only between the armature break and field break and there was no effect on the armature contact, but what effect there was was entirely at the field contact break, so that this arrangement appears to be justified. Contd. | ||