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).
Translated letter from Société d'Exploitation Commerciale des Appareils Marchal answering queries about a dynamo and ignition coil.
| Identifier | ExFiles\Box 60\4\ Scan116 | |
| Date | 8th December 1931 | |
| Translation. -------- X6099 Letter from the Société d'Exploitation Commerciale des Appareils Marchal, of Neuilly (Seine - France) December 8th 1931 Dear Sir, Your letter of the 26th of November of November has had our best attention and we have much pleasure in answering hereafter your two queries: 1) The output indicated for our Fh dynamo (130 mm ø) corresponds to working conditions similar to those obtaining on a car, that is to say, dynamo being mounted on the crankcase, which permits of the evacuation of the calories and an equilibrium of temperature between the mass (? earth) of the dynamo and the mass (? earth) of the engine. We think that the working temperature is then from 70 to 80° C. at the most and at such temperature neither the coils nor the soldering of the armature are exposed to any risk. This machine being very well balanced electrically, there is no exaggerated local overheating, and especially, the commutator does not get overheated through the commutation sparks, these being practically nil as long as the speed limit indicated in our diagram is not exceeded. 2) When designing our ignition coil, we have solely striven to attaining a high electrical output and a very large range of utilisation. In effect, our coil permits of obtaining an efficient spark at a frequency of 300, which corresponds to | ||