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).
The examination of Dynamo No. 197, identifying projecting micas as the cause of burnt commutator bars and requesting reconditioning.
| Identifier | ExFiles\Box 50\5\ Scan264 | |
| Date | 13th November 1923 | |
| X. 4333 Mr Brock. c. EP.{G. Eric Platford - Chief Quality Engineer} c. EFC. BY2-P13.11.23. X.4333 DYNAMO NUMBER 197. WILLIAMSON. In dismantling and examining the armature of the above Dynamo, it was noticed that one or two Commutator Bars were burnt away, evidence that the micas were projecting. In order to make sure that the wear on the Commutator was not excessive, and was the direct cause of the trouble by exposing the micas, I have measured the diameter of the unworn ridge on the Commutator. The difference in diameter is only .006", and as we have always called for the mica to be cleared away .012" below the surface of the Commutator Bar, I consider that the cause of this trouble is that the micas were not cleared away sufficiently in the first place - I therefore think the expenditure necessitated in dealing with this matter should be charged up R.D.W. Will Mr Brock kindly clean up the Commutator and recondition the Dynamo itself, when same will be ready for use again, either on the original customers car, or for replacement work, preferably the latter, as one does not wish to again put the customers car out of service whilst rechanging the Dynamo. BY.{R.W. Bailey - Chief Engineer} | ||