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).
Experimental proof for the use of 28 slot armatures on 40/50 HP dynamos.
| Identifier | ExFiles\Box 68\4\ scan0029 | |
| Date | 16th November 1927 | |
| X8672 To EY. from EFC, c. Mr. Brock. c. MX.{John H Maddocks - Chief Proving Officer} Wor.{Arthur Wormald - General Works Manager} EFC4/T16.11.27. RE 40/50 HP. DYNAMOS. X8660 X8671 We have had further experimental proof, carried out by the Test Dept. in conjunction with ourselves, of the efficacy of the 28 slot armature in getting rid of any noisiness that may remain in single modification machines as compared with the old standard. We wish to draw your attention to the technical advisability of utilising the 28 slot armatures on any further machines of this type that are to be built, provided it is expedient in other ways. It occurs to us, for instance, that if you have a number of 29 slot armatures on hand, these might be held over for use on the N.B. machines when these come on, as it is only the position of the commutator that is a bit different. We have urged from time to time the placing of N.B. dynamos on production, and it may be that we have arrived so nearly at this point that the use of the 28 slot armature on the present machine is not worth the change. We wished, however, to put the position to you, viz. that so far as present machines are concerned, we have now completed our experimental proof of the usefulness of the 28 slot armature in this direction. Owing to the fact that we have already completely standardised the N.B. machine, we should not propose to circulate a standardisation sheet for an alteration to a machine which is obsolete from our point of view, and therefore it rests with you as to what is expedient to be done. Our further work with the 28 slot armature will be in regard to the use of these on the N.B. machines, in order to have the circumstances of its use on such machines ready in case it should happen that there are any complaints of noise whatever from these N.B. machines with the 29 slot armatures when they come along. Referring again to the single modification machines, as we have already arranged that the output be set to the specification by moving the control brush, not necessarily keeping to the control brush angle specified thereby, any change in output caused by the change of armature would be automatically corrected for on production, though we have proved that on the average the output is materially unaffected. EFC. | ||