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).
Faults and investigations on several 20 HP dynamos.
| Identifier | ExFiles\Box 57\2\ Scan062 | |
| Date | 22th December 1926 | |
| To EY. from EFC. c. Mr. Brock. X5783do EFC3/T22.12.26. X.5783do. 20 HP. DYNAMOS:- No.191 Ex chassis 72A5 - C'wood. No.1123. " GLK7 - ? No.1676. " GSK.61 - C'wood. No.1214. " GNK.55. - " No.191. This is a 29 comm. segment machine. Solder has run because (1) The control brush is too far retarded, 115º in place of 122º (29 segs). (2) Slightly projecting micas, causing brush sparking. In addition the dynamo has the following faults:- The positive brush is a negative brush inserted the wrong way round. The positive brush spring is of incorrect shape. Owing to the accumulation of brush dust the insulation would not stand up to the 200 volt A.C. test. This applied also to the armature, which is not usual. No.1123. This is a 29 comm. segment machine. The commutator connections of this machine have been re-soldered, but apparently not by ourselves. The positive brush spring jamms in the brush slot, preventing the machine from self-exciting on our test. Otherwise there is nothing really wrong with this dynamo, and we found that it would generate normally. There is insufficient evidence of the running of the solder having been due to any faults in the machine itself. No.1214. This is a 29 comm. segment machine. The trouble with this dynamo was that the brushes were sticky in their holders with a mixture of oil and carbon dust, and this was cured by cleaning these parts with petrol. No other fault. No.1676. This is a 57 comm. segment machine. We do not find anything wrong with this machine whatever, insofar as performance may be affected. There was, however, a loose lubricator. contd. | ||