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).
Instructions for modifications to a dynamo armature for the 40/50 chassis, based on a visit with Mr. Royce.
| Identifier | ExFiles\Box 68\4\ scan0218 | |
| Date | 30th May 1921 | |
| To Ds. from EFC. c. By.{R.W. Bailey - Chief Engineer} c. De/Thr. c. Ey/WHR.{Mr Wheeler} c. HIC. X.3526 - R.H. EXPL. DYNAMO FOR 40/50 CHASSIS MADE FROM STARTER MOTOR PARTS. Our visit to Mr. Royce has resulted in modifications of the previous instructions in connection with the above job. Mr. Royce wishes to cut out altogether the armature previously instructed with the 45 slots of narrow and deep section, and to replace this by an armature very similar to the 37 slot armature, but containing six turns per section of 19 S.W.G. in place of the eight; the result being that we shall have two armatures each of 37 slots of equal width, but with slot depths in the ratio roughly of 3 to 4. Thus the numbers of conductors will be 592, as already instructed, and 444. This matter has been explained verbally to Mr. Thacker who will now put this modification through. The matter of armature windings for both dynamos and starter motors was discussed at some length with Mr. Royce and he has instructed that all wave wound four-pole armatures should have numbers of slots which correspond to the formula 4 m + 1, where m is some whole number. The pitches both of the coil or back end and of the connections at the commutator end are to be equal, (which corresponds to conductor pitches of two consecutive odd numbers alternately). This results (with the number of slots given by the above formula) in a winding which is retrogressive in every case and which will give, in Mr. Royce's opinion, the best commutating armature. | ||