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 of commutators on the Goshawk 11 dynamo and proposing material and design changes.
| Identifier | ExFiles\Box 50\5\ Scan056 | |
| Date | 19th May 1922 | |
| To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to Sd. c. to By.{R.W. Bailey - Chief Engineer} c. to Hy.{Tom Haldenby - Plant Engineer} c. to FP.{F. Potts} c. to FPC. [handwritten] X4333 [handwritten] Seen Hs{Lord Ernest Hives - Chair} R2/M19.5.22. X4333 RE GOSHAWK 11. DYNAMO. Referring to the bursting of the commutators, I under- stand that this has occurred on the dynamos only and not on the starter motor. We have noticed in the model piece sent to us that the bakelite was cracked in a way which is very likely to cause the failure experienced. We have sent an altered design in which the tendency to crack should be very much reduced, and also provision is made for supporting the bakelite before removing the band on the out- side of the commutator. Since the commutator is very nearly right one would ex- pect this to make it quite reliable especially if improved mater- ial can be found. We ought to consult the bakelite people as to whether a [handwritten] still and [/handwritten] different material than the standard is used for this purpose, [strikethrough]for[/strikethrough] [handwritten] or [/handwritten] the difference of moulding pressure. In my [strikethrough]two[/strikethrough] [handwritten] 3rd [/handwritten] suggestions I have replaced much of the [strikethrough]micanite[/strikethrough] [handwritten] bakelite [/handwritten] [handwritten] with [/handwritten] steel, asking the [strikethrough]micanite[/strikethrough] [handwritten] bakelite [/handwritten] to only do compression work, and leaving the steel for the tension and other duties. If it is practical to use this arrangement we should expect this would be very much more reliable than the wholly bakelite support. My third suggestion to clear this matter up quickly for immediate production is to make the commutators in the more orth- odox and old-fashioned method, with micanite rings and steel hubs. This would be a perfectly safe policy and would be in a line with most of the European makers, (C.A.V. etc.). It is a scheme in which we should have confidence to go ahead until we had provided (1) | ||