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).
Test and mileage log for a main and auxiliary switch unit with mechanical interlock, designated Unit B.
| Identifier | ExFiles\Box 64\4\ scan0277 | |
| Date | 23th May 1929 | |
| X7655 Main and Auxiliary Switch unit with mechanical interlock for Sequence Starter Unit B ELECTRICAL EXPERIMENTAL RECORD SHEETS. Date on. | Location. | Date off. | REMARKS. | Miles reading Start. | Miles reading Finish. | Miles Covered. | Total Miles. 10-12-28 | lab. | | Received from shop and tested on bench | | | | 11-12-28 | | | Tested with starter on engine. OK. E7Co gaps. | | | | 12-12-28 | 18EX | | Fitted to 18EX. | 00839 | | | 26-12-28 | " | | Copper contacts burnt slightly. | | 6242 | 5403 | 5403 23-5-29 | " | 23-5-29 | Removed from chassis and examined in lab. | | 17987 | 11745 | 17148 23-5-29 | lab. | | Dismantled as this switch was out of date. | | | | | ||