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 of E.A.C. and Lucas E.575 dynamos with varying temperatures, belt drive ratios and pole piece materials.
| Identifier | ExFiles\Box 36\4\ scan 255 | |
| Date | 5th December 1923 | |
| X.3014B X.9660 - E.A.C. DYNAMO. X.3014B The Lucas E.575 machine in the fully hot condition puts up 13.6 volts at 720 R.P.M. At 75°C (in accordance with general specification) the speed might be approximately 665 R.P.M. This lower speed, with the original 1.56 belt drive ratio, would correspond to a road cutting in speed of 12.75 m.p.h. With the later belt drive ratio of 1.7, the speed would correspond to a road cutting in speed of 11.7 m.p.h. The E.A.C. machine, as originally arranged with cast iron pole pieces to put up at 75°C 13.6 volts at 575 R.P.M., would, with a 1.56 belt drive ratio give a road cutting in speed of 11.0 m.p.h. Arranged with mild steel pole pieces to put up 13.6 volts at 75°C, at 500 R.P.M., it would, with a 1.5 belt drive ratio, give a road cutting in speed of 10.0 m.p.h. EFC. | ||