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).
Testing of commutator segments using a voltmeter to determine brush positioning.
| Identifier | ExFiles\Box 50\1\ Scan247 | |
| Date | 22th October 1923 guessed | |
| -2- while two adjacent commutator segments were connected to a voltmeter. The armature was moved round until the alternate voltmeter deflections ceased, and the position which the main brushes would occupy was marked. The angular distances of the line between the two test segments from the centre-lines of the main brushes were then compared. Three such tests were made (as there are three coils per slot) using successive pairs of commutator segments, the results being (1) 4° advanced, (2) 4° retarded (3) 1° retarded, for the actual position of the main brushes, an average of 1° retarded. RJA. MADE AT CROXLEY | ||