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).
Assistant's report on an overheated Dynamo No. ES.75 from Chassis 95-HC.
| Identifier | ExFiles\Box 70\3\ scan0324 | |
| Date | 2nd November 1927 | |
| X8783do To BY.{R.W. Bailey - Chief Engineer} from EFC. c. Mr. Brock. EFC6/T2.11.27. DYNAMO NO.ES.75 EX CHASSIS 95-HC. Please find below copy of my assistant's report PD.11 on the above machine, which we now return to BY.{R.W. Bailey - Chief Engineer} :- "This appears to be a case of the armature having become overheated and melting the solder at the commutator connections, causing a break in the circuit of the armature winding. There were found two flats, worn on the commutator, as a result of flashing due to this open circuit in the winding. The commutator otherwise appeared O.K. It was also found that newbrushes had been fitted. Of these, the outer positive and the inner negative brushes were interchanged. All brushes had evidently had little running and apparently had been fitted in an attempt to remedy the flashing taking place. Overheating was most likely due to excessive output as a result of the control brush position for the reasons that :- (1) The armature had been overheated all through; the solder having also been melted from the banding wires on the pulley end. (2) The field coils also appeared to have been overheated. (3) The control brush angle was about 121° from the positive brush, which would make the output be on the high side. The insulation of the control brush holder was found to be bridged by carbon dust and consequently faulty." EFC. | ||