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).
Procedure for testing and bedding in dynamo brushes.
| Identifier | ExFiles\Box 70\4\ scan0071 | |
| Date | 6th November 1926 guessed | |
| -2- Contd. (e) The connections of the pigtail conductors are not in any way damaged. (f) The initial bedding of the brush shews 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. 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, 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 1300 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. 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 at some place for an axial distance not less than .050"). (4) Final bedding of brushes. With end cover removed the dynamo shall now be run on load at 1300 r.p.m. for 3½ hours charging at an operating voltage between the limits 17.0 and 18.0. This should render the brush bedding finally satisfactory. Contd. | ||