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).
The investigation, faults, and repair of a dynamo sent for a No.4 Goshawk engine.
| Identifier | ExFiles\Box 51\1\ Scan086 | |
| Date | 19th July 1922 | |
| To EFC. {E. Fowler Clarke - Electrical Engineer} from R. {Sir Henry Royce} c. to Wor. {Arthur Wormald - General Works Manager} By. {R.W. Bailey - Chief Engineer} c. to Mr. Brook. X4383 R2/M19.7.22. X.4383. RE DYNAMO SENT FOR No.4 GOSHAWK. X.4383. Owing to the absence of the coloured wire scheme, with the ends of the wire not being permanently marked, we had to exercise some ingenuity to find the correct wires to put on the dynamo. This was done however before the dynamo was tested. On joining up, the machine did not excite itself and the fuse was found to be blown. After replacing the fuse, the cutout shattered, and the ammeter vibrated badly, coinciding approximately with the speed of the armature, and again the fuse blew. After another similar attempt it was concluded that there was a broken wire on the armature. On taking the dynamo down however it was found that the spaces between the commutator plates was blocked with carbon dirt, and possibly the surface of the commutator was not clean. After carefully cleaning out the gaps, the machine was re-erected and worked perfectly. In addition to this temporary fault, the ball bearings at the minor end appeared to rumble and to be slack. These appear to need carefully testing. I would like to warn the Production Dept. to use plenty of heat while pressing up the commutator, and every endeavour should be made to see that the commutator plates are firm. It might be desirable to run the commutators in an overheated condition at very much over the running speed. | ||