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).
Examination of a faulty dynamo from chassis 68-SC due to a high output complaint.
| Identifier | ExFiles\Box 70\3\ scan0297 | |
| Date | 25th June 1927 | |
| XR78320 To BY from EFC. c. SFT{Mr Swift}/Mr. Brock. EFC4/T25.6.27. 40/50 DYNAMO TA.35 EX CHASSIS 68-SC. We have duly examined this machine, the complaint of which was high output, and have noted the following points as quoted from my assistant's report P.C.140 :- "From examination and test of this machine the following points were noted :- (1) On testing the insulation of the complete machine, a partial breakdown was observed. This was subsequently found to be due to carbon dust bridging the insulation of the control brush holder. (2) The inner control brush, and both negative brushes were found to be sluggish in their respective holders. The outer negative brush in particular was sufficiently gummed in its holder (by a mixture of oil and carbon dust ) to render the spring useless. (3) The surface of the commutator was blackened, but the surfaces of the brushes were in reasonably good condition. (4) Solder was found to be melted from the commutator connections, but the armature otherwise appeared to be alright. (5) The control brushes were found to have the early setting of 120° from the main positive brushes. The high output complained of, and which appears to have been the cause of the solder at the commutator melting, was most likely due to the 120° setting of the control brushes. It seems unlikely that the high output was due to the stickiness of the negative brushes, as the inner negative brush was sufficiently free to make good contact and both brushes had good surfaces." Dynamo is herewith returned to BY.{R.W. Bailey - Chief Engineer} EFC. | ||