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).
Suggested revision to the inspection and test specification for the 40-50 HP starter motor.
| Identifier | ExFiles\Box 62\1\ scan0178 | |
| Date | 19th October 1933 | |
| Hs{Lord Ernest Hives - Chair}/Wst. 26079. BY/RD5/W.19.10.33. WST 40-50 H.P.Starter Motor. Specification of Inspection and Test,Version 2. On looking into this 40-50 H.P.Starter Motor trouble I find that under Paragraph 1,Sub section "F", you ask them as follows :- "Verify that the armature operated switch makes contact for the last .300±15 of armature motion." In the previous paragraph you permit a total armature motion of .775±15. The Works,I find,are rigidly working to this and in cases where the armature travel becomes .760" they arrange for .300" armature movement with switch operated, hence the balance .460" is the initial movement to operate switch. This,of course,is all wrong and is like putting the cart before the horse. What we have discovered,of course, shows that the Works have been carefully getting correct the last portion of the stroke which is unimportant ; the first and important half has suffered by the varying limits which occur in the armature stroke. Also,we find that the ±15 limit on total armature stroke is exceeded,and as many parts are used and no harm can occur we recommend that ±30 is more suitable. We suggest that you rewrite that paragraph,as follows :- "Verify that the armature operated switch makes contact when the armature has moved .475±25 and remains on contact for the remainder of the armature stroke. If necessary adjust contact gap to give this condition,which gap should be .040±10". BY/RD. | ||