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).
Revised specifications for the contact gaps and spring tension of a combined main and relay switch unit.
| Identifier | ExFiles\Box 64\3\ scan0185 | |
| Date | 31th October 1924 | |
| To RHC.{R. H. Coverley - Production Engineer} from EFC. X8650 EFC5/T31.10.24. X.8650. COMBINED MAIN SWITCH & RELAY SWITCH UNIT. As regards the relay switch unit, we stated in our EFC2/T30.10.24, that the contact gaps as at present arranged are reasonably in accordance with the table which we shall give. We have now revised our specification of contact gaps and it is considered that those between the armature and the core should all be reduced, if possible, by raising the armature core another 15 thous. The observed gap in the 'on' position of the switch when last in our hands was .029". We are now specifying .015 +5 -3 and we should like, if possible, to alter it to this. As regards the tension of the spring, this is found to be O.K. on the top contact, but owing to the spring tension increasing rapidly as the switch arm was depressed, this was too little on the bottom contact, when the switch was worked. As explained we want the spring to be such that it does not rapidly change its tension, due to the motion of the armature, but increases due to this motion only a relatively small amount. This, as previously expressed, is the equivalent of a lower rating with a bigger set. Contd. | ||