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).
Procedures and results for dynamo and regulator testing at various speeds.
Identifier | ExFiles\Box 166\2\ img231 | |
Date | 21th December 1938 | |
2. 21.12.38. R.E. Davis, Esq., Messrs. Rolls Royce Ltd., that the load characteristic should be checked by means of running up the set with a 10 amp load in circuit. This has been discussed in Birmingham, and it is considered that a more suitable method would be to run the set up to the chosen speed on open circuit conditions and then to gradually increase the load to the correct value. This method avoids any shock to the regulator and will give more consistent results. The question of the best speed to run the dynamo for checking the regulator characteristics has been considered, and bearing in mind the limitations of the motor in the Rolls Royce laboratory, 4,000 r.p.m. seems to be the best speed, although we wonder if this is not rather high when considered in conjunction with the equivalent road speed of the car. It has been our practice to set the regulators on our own dynamo operating at 1,450 r.p.m. and to check the amount of rise of the output characteristic at 3,000 r.p.m. If the 4,000 r.p.m. on the Rolls Royce dynamo is adopted, then it would appear to be necessary for us to check at a higher speed than is our present practice, and the most convenient one for us would be 3,000 r.p.m. Whilst the readings at this speed would not be quite the same as those obtained on a R-R machine at 4,000 r.p.m., the results on the one test can readily be interpreted in terms of the other. Working on these lines we have arranged to set regulators on the limit values of 15.6 and 16v on the Lucas machine running at 3,000 r.p.m. and then checking on the R-R 5" dynamo running at 4,000 r.p.m. The results obtained were as follows :- Output at 13.5v 15.5 - 18.5 amps measured through A1 terminal. " " 15.5v 4.5 - 8.5 amps measured through A terminal. The corresponding open circuit voltages on the regulators would be 16.0 - 16.4. These figures are very closely in agreement with those mentioned to you on Monday last, and I suggest them to you as being | ||