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).
Specification outlining the testing procedures for a dynamo, including insulation, load, and performance tests.
| Identifier | ExFiles\Box 168a\3\ img092 | |
| Date | 13th December 1938 guessed | |
| -2- SPECIFICATION. R.C.158. (2) The insulation resistance of the machine should be taken and should not be less than 1 megohm. N.B. For the running tests it will be necessary to insert a variable resistance in the field circuit of the dynamo. A second variable carbon resistance is used in the main circuit with which to adjust the terminal volts. (3) With the end cover removed, and field resistance short circuited, the machine shall now be run on load for 3 1/2 hours at an output of 20 + .5 amperes at 13.5 volts. During this run, the commutator should be frequently wiped if necessary, to ensure that it is free from grease or varnish deposit. Notice should be taken of the brushes in respect of noise. Any undue noise should be investigated and rectified, if necessary re-skimming the commutator. This run should render the brush-bedding finally satisfactory, and allow time for the machine to heat up and reach a final temperature. (4) Immediately after the termination of the above run, the speed and voltage shall be carefully adjusted until the output of the machine is 20.0 + .2 amperes at 13.5 volts, when the speed should be measured. This should not exceed 1750 r.p.m. (5) With the dynamo still in the same hot condition it should be verified that running on open circuit it shows a voltage of 13.0 at not more than 740 r.p.m. (6) The dynamo shall again be run on load and its speed varied up and down with a view to testing for mechanical and electrical noise. (7) The dynamo shall now be run up to 5,500 r.p.m. still on load, the field resistance being progressively increased as the speed increases, and shall show no abnormal brush sparking when delivering 20 amperes at 13.5 volts. Further the mechanical vibrations due to any want of balance shall not be excessive. (8) Examine also for rubbing armature, slack bearings, cracked insulation and final condition of commutator, and brush surfaces, and see also that with the dynamo hot, the end cover can easily be put on and taken off. | ||