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).
Technical memo diagnosing a fault in a Dynamo W.45 X from Chassis 7-LC, suggesting arcing caused by foreign material.
| Identifier | ExFiles\Box 70\3\ scan0283 | |
| Date | 16th March 1927 | |
| X8783 To BY.{R.W. Bailey - Chief Engineer} from EFC. c. Mr. Brock. DYNAMO W.45 X. EX CHASSIS 7-LC. Attached please find my assistant's report Pc.129 in connection with the above dynamo. It is difficult to give a definite diagnoses of what has happened to this machine. It appears possible that the positive terminal was earthed on to the carcase, while the machine was working, by some foreign material, and that possibly some of the fuses were fused. Upon removing the evidence of arcing in the form of a powdery deposit, a track was discovered along the surface of the metal near to the positive brush and just under the positive screw making connection to the positive terminal. It is difficult to think that this deposit and track can have been produced by anything else than an arc, and it is difficult to see how the arc has been struck, in the absence of some foreign metal, and unless the dynamo was running on open circuit at the time. In any case it appears that this dynamo has been run in some peculiar circumstances, as we do not think there is sufficient explanation of the running of the commutator solder, judging from the ordinary condition of the brushes and commutator itself, and the fact that the control brush angle is not such as to make the machine give a very big output. All the evidence is that something abnormal has been done to the machine for which we consider, unless policy dictates otherwise, the customer might be had responsible. Machine herewith. EFC. | ||