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).
Letter responding to F.H. Royce regarding design considerations for alternating current motors.
| Identifier | Morton\M6\ img086 | |
| Date | 4th June 1928 | |
| GC 4628 JCM. 4th June, 1928. F.H. Royce Esq., "ElmsteadHenry Royce's home in West Wittering", West WitteringHenry Royce's home town, Nr. CHICHESTER. Dear Mr. Royce, ALTERNATING CURRENT MOTORS In reply to your letter of the 19th ultimo., this has been carefully considered by myself, Mr. Coley and Mr. Huggins of the Electrical Department. I think the motor with the enclosed reduction gear will prove a useful machine, for both A.C. & D.C. work, it will, however, require carefully developing and therefore must give way to more important work for the time being. ALTERNATING CURRENT MOTORS:- (1) - Yes, we all agree that slip rings inside the bearings will be best, and it will be on these lines we shall make our designs. (2) - We always make a practise of taking end thrust on the main bearing wherever possible using the deep groove "no gap" bearing for the purpose. In the case of particularly heavy duty where it is necessary to use Roller Bearings there is no real reason why the end thrust should not be taken on the minor bearing. This end thrust is not an excessive thrust and the minor bearing can be of a sufficiently rigid construction without it being expensive. (3) - I do not agree with your remarks that we ought to make the bearings so that they are easily removable. We can always make our rotors or armatures easily removable without disturbing the actual bearings; there are several ways of obtaining this result. In the past we have always had failures where the bearings have been easily removable, and no failures where they have been pressed on to the shaft. We do not like the quick taper and nut, neither do the ball bearing makers. The coned shafts are expensive to make, and having made the provision users will endeavour to remove the bearings and cause more damage in removing and replacing them. Almost 90% of the motor makers are now definitely either pressing the bearings on to the shafts or shrinking them on. | ||