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 calculations and suggestions for a scheme sequence starter motor.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 194 | |
| Date | 22th June 1927 | |
| To R.{Sir Henry Royce} from EFC. c. BJ. BY.{R.W. Bailey - Chief Engineer} c. BY/RD. ORIGINAL EFC5/T22.6.27. X7625B NO. 2.B. SCHEME SEQUENCE STARTER. Further to our EFC/HEW3/T15627, we now send you revised calculations based on the 16 : 1 gear ratio, to suit 45 slots with one turn per section. With this number (90) of conductors and this gear ratio, we think the motor should be reasonably satisfactory, the magnetic density through the teeth being considerably easier. As in previous cases these calculations are in the nature of an estimate and we therefore recommend that one (or two) more turns per pole of main excitation than calculated be tried experimentally. Our actual suggestions for field excitation to be tried in the first instance are :- (1) On each of the four poles 36 turns of 17 SWG. teaser winding plus 3 1/2 turns of main, of as much section as possible. (2) On each of two opposite poles as many 17-SWG teaser turns as possible, and each of on the other two poles 7 1/2 turns of main winding of as much section as possible. We are passing a copy of these figures on to the D.C. for their approval of the proposed slot and insulation dimensions, and to enable them to make drawings of the details of the field poles and conductors and of the field windings. These calculations are based on a non-taper armature of 3.100" diameter. We feel that we cannot afford to lose the armature winding space which will be lost by using punched plates, and then grinding to a taper - in addition to which there might be some | ||