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).
Noise issues with a lighting dynamo, caused by vibration from laminated pole pieces.
| Identifier | ExFiles\Box 68\4\ scan0232 | |
| Date | 3rd January 1925 | |
| To EFC. from E.{Mr Elliott - Chief Engineer} c. to CJ. X1640 E2/M3.1.25. RE LIGHTING DYNAMO AT WW. X.3362. X.1640. X.294. In response to your query concerning the above, I have no information regarding three armatures for this machine. I can only tell you that it has been run with one of the three armatures you mention and runs very silently. Our latest information concerning dynamo noise as supplied by Mr. Bentley during his recent visit here to see Mr. Royce was that it was mainly caused by the laminated ends of the pole pieces which set up a vibration. The long attenuated ends of the pole piece stampings could not be effectively fixed together, and when replaced by solid pole piece ends it is said that the singing noise disappears. It would no doubt be advantageous to make a comparative test of this at the Works. MADE AT CROXLEY E.{Mr Elliott - Chief Engineer} | ||