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).
Persistent faults found in a 20 HP Dynamo No.94, ex chassis 63-H6, with recommended corrections.
| Identifier | ExFiles\Box 57\2\ Scan075 | |
| Date | 28th March 1927 | |
| To BY.{R.W. Bailey - Chief Engineer} from EFC. c. Mr. Brock. X57820 EFC1/T28.3.27. 20 HP. DYNAMO No.94. EX CHASSIS 63-H6. This is a 29 commutator segment machine and has been to us previously and reported upon in our EFC4/T22.12.26. We there gave the reasons of the solder having melted - (a) Control brush too far retarded, 115° in place of 122°. (b) Projecting micas. (c) Negative brush spring jams in slot causing bad sparking at negative brush. Present examination reveals the fact that the items (a) and (c) still apply, as if presumably they have not been corrected, i.e. - (a) The control brush is too far retarded, 115° in place of 122°. (b) Negative brush spring jams in the brush slot causing the spring not to act correctly on the negative brush. This has been the cause of sparking and has considerably assisted in overheating the machine. The negative brush should now be replaced with an up-to-date brush with the bevel top and it should be carefully ascertained that the condition of the brush and commutator system is correct before the machine again leaves. We return the machine to BY.{R.W. Bailey - Chief Engineer} It occurs to us that the control brush angle may have been corrected, but that it has been re-set, because there is a mark which at which it is set. We think, therefore that this mark should be removed if possible and a new mark made to give the now correct position of the control brush. EFC. | ||