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).
Inspection report for a Goshawk Dynamo 184 following a failure complaint.
| Identifier | ExFiles\Box 47\4\ Scan154 | |
| Date | 9th January 1924 | |
| EFC. AB.98. COPY 9th Jan. 1924. GOSHAWK DYNAMO 184 (COMPLAINT). This machine was received from Ey. for inspection after failure; it is one in which the main brushes are in the old standard position. The commutator was not burnt though a little rough and the brushes were well bedded but not highly polished. Spring pressures were below what is now specified being .4 lb all round; the brushes were an easy fit in the holders. The negative brush was found to be at a "trailing" angle, so that the main brush spacing was a little wide. The control brush was found fully retarded, the carrier piece having been cut away to accommodate this and the brush itself was at a trailing angle. The effect of this was to leave less than eight clear segments between it and the positive brush, whereas well over eight are normally left. The output was therefore high, and after 20 mins running on the bench was 12.5 amps, sparking was also rather bad. Probably the output was found moderate, with the control brush fully retarded, owing to its bearing only on the leading edge, then when it became bedded the output increased and caused the damage. The armature connections were soldered up before testing. The negative and control brushes are earthed by carbon dust. EFC/FJA. | ||