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).
Instructions for the testing and main bedding-in of dynamo brushes and commutators.
| Identifier | ExFiles\Box 62\3\ scan0123 | |
| Date | 22th January 1931 guessed | |
| -2- (e) The connections of the pigtail conductors are not in any way damaged. (f) The initial bedding of the brush shows partial contact reasonably well distributed over the working surface. (Preliminary bedding of brushes). (2) The insulation resistance of the machine should be taken and should not be less than 1 megohm. N.B. (1) For the running tests of the dynamo there must be no armature end play. It may be necessary to insert washers between the temporary driving pulley and bearing so as to keep the armature up towards this bearing, i.e. in the position which it will have when fitted on the chassis. (3) Main bedding of brushes. The dynamo shall now, starting cold, be run on load at about 1600 r.p.m. charging a 12-volt battery of ample capacity and the condition of the brush bedding observed and improved from time to time, if necessary. At the same time the commutator should be frequently wiped with a clean rag to ensure that it is quite free from a grease or varnish deposit. This should continue until the working surface of each brush shews evidence of making contact across the whole thickness of the brush (i.e. in the direction of the commutator circumference atsome place for an axial distance not less than .050"). Any tendency of the control brushes to blacken along their trailing edges should be allowed to continue unless it is obviously due to excessively bad commutation. | ||