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).
Report investigating an overheating electrical fault in the dynamo cut-out on chassis 50-RC.
| Identifier | ExFiles\Box 70\3\ scan0202 | |
| Date | 9th September 1926 | |
| X8783 db{Donald Bastow - Suspensions} EFC. Mr Brock BY5/H.{Arthur M. Hanbury - Head Complaints} 9.9.26. CHASSIS 50-RC.{R. Childs} Referring to EFCb/T. 1.9.26. on receipt of your report, and reading same, I carefully inspected the bolt which secures the dynamo "A" wire to the cut-out, but could not find any evidence that this particular connection was the cause of the trouble. It is quite clear that the fixed cut-out contact point and support, and the bolt securing same, have been extremely hot, in fact, hot enough to cause the solder to run which locks and secures the heads of the bolts, but the evidence appears to indicate that the heat which caused this has travelled down from the contact point itself, as the contact appears to have been subject to the highest temperature of any of these parts. Inspection of the parts would lead me to conjecture that the upper contact point had made a bad connection, as there is a distict gap between the spring arm and the contact piece, and that this would be responsible for a certain amount of over-heating; contact being poor would heat up the contact on the fixed support, and the heat would then travel down the bracket in question to the base of same, causing the solder to melt. I have just received a further memo on the subject from Cricklewood, to whom I wrote pointing out the need for carefully inspecting the whole of the electrical system if a dynamo failed, and am surprised to learn that on two occasions new dynamos have been fitted, prior to the whole of the units being returned. It is therefore evident that the dynamo itself was not at fault, and it is most probable the trouble is located in the cut-out. A fault of the nature suggested above would result in a high resistance being brought directly into the battery and dynamo circuit, which would put up the voltage and output again, and result finally in the burning out of the dynamo. I am returning the distribution board to you so that you can check the points to which I make reference in this memo. Contd. | ||