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 providing specifications for the X.9620 starter motor windings.
| Identifier | ExFiles\Box 64\1\ scan0158 | |
| Date | 13th October 1923 | |
| To EFC. from R.{Sir Henry Royce} S E C R E T. Rl/M13.10.23. x7620 E.A.C. X.9620 - STARTER MOTOR. Referring to your memo EFC5/T5.10.23., 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/T19.6.23. MAIN FIELD WINDING. 6¼ turns per pole of copper tape of section shewn on LeC.1770 of cross sectional area of .012 sq.ins. TEAZER FIELD WINDING. 36½ turns per pole of [text struck through] No.18 S.W.G. (.048") dia. copper wire. MADE AT CROXLEY R.{Sir Henry Royce} | ||