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).
Conclusion of a test report on dynamo armature improvements and high-speed performance.
| Identifier | ExFiles\Box 60\3\ Scan245 | |
| Date | 14th September 1933 | |
| -3- Hg/Wat.3/WA.{Mr Wallis}14.9.33. Cont'd.{John DeLooze - Company Secretary} This increase is very small in view of the much improved high speed performance of the machine. The other armature tried had plates of "Lohys" iron. "Lohys" has a better permeability than "Stalloy" but has a higher iron loss, approx. 50%. Due to its higher permeability a slightly lower "cutting in" speed was realised with this armature but its output performance was not as good as the "Stalloy" armature, being 14.5 amperes at 13 volts at low speeds dropping to 13.3 amperes at 5000 R.P.M. With both armatures a considerable improvement was noted in the commutator sparking at high speeds it being possible to maintain full output at 5000 R.P.M. without undue brush distress. We attribute this largely to the reduction in armature reaction obtained by using a smaller number of armature conductors. Conclusion. The results we have obtained with these armatures represent a big step forward in the improvement of our chassis dynamo for the high speed conditions now required by our latest chassis. These results will also enable us to similarly improve our 20/25 size dynamo. Hs{Lord Ernest Hives - Chair}/Wat. | ||