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).
Revised and more efficient production testing specification for dynamos.
| Identifier | ExFiles\Box 168a\3\ img094 | |
| Date | 30th May 1938 | |
| To By 6142 Rm{William Robotham - Chief Engineer}/RC.{R. Childs}8/JH.30.5.38. PRODUCTION TESTING OF DYNAMOS. With a view to facilitating the production of dynamos, we have reviewed the specification of test for these machines, and produced a modified form of it. This has been done without, we consider, reducing in any way the efficiency of the test. The feature in the present method of testing dynamos, which attracts most attention, is the time spent on running the machine. It will be seen from the specification that the two long periods of running (tests 3 and 4) are for the following purposes:- (1) The bedding of the brushes. (2) To observe for brush noise, and grease etc. on the commutator. (3) To heat up the machine with a view to the high temperature revealing any incipient fault. (4) To heat up the machine for the purpose of measuring its output (5) To ensure the exposure of any incipient fault by running in conjunction with a high temperature. With reference to these points it will be seen that if (1) the brush bedding could be almost completed on assembly, and (3) and (4) the machine could be heated up in an oven, then only a short run is required for the purpose of (2) and (5) and the completion of (1) and (4) Tests have been made which show that if a machine is maintained in an oven, at a temperature of 150°C. for 30 minutes, a comparatively short run of one hour immediately following, is sufficient to produce the same conditions for the various purposes, as are at present obtained. Thus test (3) as at present can be eliminated, while the 3½ hours running in test (4) can be reduced to one hour. | ||