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 results for a machine under standard and modified conditions, comparing temperature rise and cutting-in speed.
| Identifier | ExFiles\Box 168a\3\ img078 | |
| Date | 5th January 1939 | |
| -2- RM{William Robotham - Chief Engineer}/RC.{R. Childs}5/JH.5.1.39. | Condition of machine. | Temperature rise on load. C°. | Cutting-in speed r.p.m. | |-----------------------------|-------------------------------|-------------------------| | Standard. | 50 | 850. | | Modified field winding. | 34 | 922. | | Brush angle reduced by 10°. | 38.5 | 855. | It was feared that the reduction in the brush angle might be detrimental to commutation, but tests shewed that there was no appreciable increase in sparking with the smaller angle. The modification may therefore be recommended for production, if a 15,000 miles road test is successfully completed. RM{William Robotham - Chief Engineer}/RC.{R. Childs} | ||