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).
Secret memo detailing the specifications for the windings of the X.9620 starter motor.
| Identifier | WestWitteringFiles\K\October1923\ Scan127 | |
| Date | 1st October 1923 | |
| R.R. 225A (100 T) (S.H 159, 11-8-20) (S. 2500) ORIGINAL 2. TO EFC. FROM R.{Sir Henry Royce} S E C R E T. R1/M13. 10. 23. E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. X.9620. STARTER MOTOR. Referring to your memo. EFC5/T51023., we now understand that Derby are working to drawings and instructions giving the following information for size and number of turns of wire for the above machine:- ARMATURE. 41 slots with 2 conductors per slot of copper tape of section shewn on LeC. 1776. and cross sectional area of .0109 sq. ins. as recommended in your calculations - EFC4/T19623. MAIN FIELD WINDING. 6¼ turns per pole of copper tape of of section shewn on LeC.1770 of cross section- al area of .012 sq. ins. TEAZER FIELD WINDING. 36½ turns per pole of No.18 S.W.G. (.048) dia. copper wire. R.{Sir Henry Royce} | ||