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 found in three 20 HP dynamos from various chassis.
| Identifier | ExFiles\Box 57\2\ Scan084 | |
| Date | 30th May 1927 | |
| TO HY.{Tom Haldenby - Plant Engineer} from EFC. c.c. SFI/Mr.Brock. X5783ko EFC2/T30.5.27. 20 HP. DYNAMOS. Dynamo No.61.EX Chassis GNK.77. This is a 29 segment machine. The solder had not run. Condition of brush and commutator system not very good, and the machine was sparking badly. Brush angles in both cases standard. Negative brush sluggish causing sparking - this was remedied by cleaning. Dynamo No.279 Ex chassis 65-H8. This is a 29 segment machine. The reasons of the solder running in this case were :- (1) Commutator micas not undercut, leading to bad brush and commutator condition. (2) This resulted in brushes wearing away unduly, all brushes wearing down to the limit and causing still worse sparking and heating. (3) Control brush angle too small, viz. 112° in place of 120°. Dynamo No.1109 Ex chassis GAK.14. This is a 29 segment machine. The solder has only just run on two segments. The reasons for the running of the solder are not very clearly evident, but the positive brush is badly worn and had at some time been taken out and inserted the wrong way round. This one brush is of the old flat-top type subsequently improved upon. The dynamos are returned to HY.{Tom Haldenby - Plant Engineer} EFC. | ||