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).
Performance comparison table of dynamo balancing speeds under various conditions.
| Identifier | ExFiles\Box 165\6\ img210 | |
| Date | 20th August 1929 guessed | |
| PERFORMANCE COMPARISON Balancing speeds. | Dynamo. | Shunt | | Controlled | | |---| 12.4 volts cold. | 13.6 volts hot. | 12.4 volts cold. | 13.6 volts hot. | | Later av: Gos. (29 segs) | 540 | 615 | 545 | 640 | | H.{Arthur M. Hanbury - Head Complaints} (29 coils) | 565 | 645 | 533 | 630 | | E.{Mr Elliott - Chief Engineer} (57 segs) | 570 | 660 | 590 | 680 | | C. (57 segs) | ø 580 | 665 | - | 682 | | Av. 57 seg. Goshawk. | 575 | 665 | 565 | 680 | | 3 coil per slot armature. | | | | 640 645 | | Std. arm. in same field. | | | | 675 680 | | Proposed new std. 600A. | | | | 680 | | ||