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).
List of standard temperatures for sentinels, detailing orders for condensers, coils, and dynamos.
| Identifier | ExFiles\Box 52\3\ Scan127 | |
| Date | 3rd October 1923 | |
| r4430 3.10.23. STANDARD TEMPERATURES FOR SENTINELS. 65° C 69° C 73° C 6 ordered for condensers. 77° C 82° C 6 ordered for coils. 87 ° C. 6 ordered for dynamos. | ||