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).
Page from a report detailing motor resistance, torque, and performance comparisons.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan026 | |
| Date | 1st July 1929 guessed | |
| -9- contd. To this end the total motor resistance should be in the neighbourhood of 6/300 = .020 ohm when cold. Actually the running value of each motor resistance is exhibited on the curves given on the ampere bases by the slope down of eg relatively to E.{Mr Elliott - Chief Engineer} In this particular instance the slope of eg relative to E is a little greater than that of E and gives an average slope of 2.15 volts per 100 amperes, indicating a hot or working resistance of the motor of .0215 ohm which agrees with actual measurements of that resistance. Correspondingly the speed torque curve of the motor does not rise unduly at low torques. It is an interesting fact that the post-war sliding armature R.Bosch motor with only 31 armature sections, appears to err in this respect on the side of too low a resistance (.017 ohm) and the stalling torque is not so good, whereas again our original sequence 41 slot motor appeared to err in the other direction with a resistance of .027 ohm, and again the stalling torque was not good. Attachments:- Ordinary brake test curves for the six motors considered. TO R.E.BY. Curves of E, eg, Ø, Ts, Tr{Capt. F. W. Turner - Finance}, etc. for the six motors considered. To R.{Sir Henry Royce} only Table of comparative brake test To R.E.By. quantities on a common basis of 90 pound-inches conductor torque. EFC. | ||