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 inspecting and testing a dynamo, covering springs, insulation, and brush bedding.
| Identifier | ExFiles\Box 62\3\ scan0455 | |
| Date | 2nd October 1934 guessed | |
| -2- Note (1) It is possible that a spring which is noticeably weak is cracked and requires replacing. Note (2) It will usually be found that a spring which is good has a uniformly expanding spiral. (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 initial insulation resistance of the machine should be taken and should not be less than 1 megohm. N.B. (a) For the running tests it will be necessary to insert a variable resistance in the field circuit of the dynamo. This should be connected between the field terminal and the negative (earthed) brush. A second variable (carbon) resistance is used in the main circuit with which to adjust the terminal volts. (b) Where there is 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 be run on load, care being taken to ensure that sufficient resistance is inserted in the field circuit to limit the output and sparking at high speed, 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. | ||