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).
Revised keying methods, insulators, boring wheels, and new ranges of D.C. and A.C. motors.
| Identifier | ExFiles\Box 180\M6\ img094 | |
| Date | 4th June 1928 guessed | |
| 6 In regard to the revised method of keying, I think this method would be very effective and would enable us to omit the key stops we now fit in many cases to prevent the keys slacking back. As a matter of fact a very similar key has been adopted by one of our competitors, Wharton of Reddish, owing to the trouble he experienced with his keys working loose on cranes fitted with squirrel cage motors, and he makes a selling point of it and carries a sample about with him. I also think we could make a split swivelling bearing cheaply, which would be a good selling point, and which would obviate the necessity of filing our shafts. Imported Insulators. I have provided the Crane Department with a design for a suitable porcelain strain insulator to take the place of the imported one, and there is an order in the works for a quantity to be made up for experiment and test. It is slightly larger than the imported one, which will necessitate the centres of the cross wires being increased in some instances, this with advantage, as they are on the close side. The only result of providing a still smaller strain insulator will be to bring the wires still closer together, and we have had trouble with the existing centres. There are many cranes going through where the porcelain design prepared can be used if they will only get on with it. They are certainly less expensive. As a matter of fact we bought globe strain insulators between the period of April 1st, 1927, to March 31st, 1928, totalling 3,000 in number, of a value of £690.2.6d. I am afraid of your method of boring wheels with a clearance. I think we should spoil a lot of wheels, and they would run badly. If bored in this manner they ought to be cut on keyed mandrels, and we cannot use keyed mandrels on either the Sunderland or the Fellows Gear Shaper. There is also the customer who replaces the worn wheels himself. I would rather make a wheel with a split boss either C.I. or use mild steel pressings similar to sketch, or a self centring centre designed somewhat on the lines of the self centring flanges used on beam ends in textile mills as per illustration attached. I am enclosing herewith the notes prepared by our Mr. Huggins, on the proposed new ranges of D.C. and A.C. machines together with the following drawings to which we refer:- General arrangement drawing of D.C. motor - B. 397. " " " of Slip Ring Motor - B. 398. " " " of Squirrel Cage Motor - B. 399. Drawing showing interchangeability of Slip Ring, Squirrel Cage, and D.C. Motors of corresponding rating. B400. It will be noted that in the case of A.C. machines foundation arrangements are kept the same whether or not a fan is fitted. The sample Brush Gear incorporating Bakelite ring together with specimen of magnetic wedge material provided by Mr. Huggins is | ||