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).
Bursting tests for moulded Goshawk commutators compared to orthodox mica and steel types.
| Identifier | ExFiles\Box 50\5\ Scan081 | |
| Date | 21th June 1922 | |
| X4333 To Wor. {Arthur Wormald - General Works Manager} from EFC. {E. Fowler Clarke - Electrical Engineer} c. By. {R.W. Bailey - Chief Engineer} EFC {E. Fowler Clarke - Electrical Engineer} 1/T21.6.22. X.4333 - COMMUTATOR FOR GOSHAWKAero EngineCodename for 20HP Car / Aero Engine after KestrelAero Engine. With reference to your Wor {Arthur Wormald - General Works Manager} 5/M20.6.20, I have the five moulded commutators supplied by Mr. Brock but am at the moment awaiting a rig from Mr. Coverley to enable speed tests to be carried out on these commutators for bursting, and he has this morning promised that this will be ready tomorrow morning when we shall get right away with the tests. X4069 For the first 100 sets instructed for the Works, however, Mr. Royce has instructed that we keep to the orthodox type of construction with mica and steel cones, and commutators both for the dynamo and motor are instructed with this construction for the 100 sets. We have every confidence that the bakelite and mica construction will eventually turn out successfully for both machines, but I presume Mr. Royce wishes to be on the safe side in the first few that are turned out. We shall be running these commutators in turn i.e. with the full amount of copper previous to turning first of all cold at 6000 r.p.m., and if this fails to burst them, we shall arrange heating units to bring them up to a temperature of 100°C or thereabouts whilst running. If they fail to burst under these extreme conditions it is considered unlikely that they would burst in service, but naturally the final test is prolonged running on the cars themselves. | ||