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).
Analysis of different electrical cutout and switchbox arrangements to mitigate sparking and component failure.
| Identifier | ExFiles\Box 65\2\ scan0060 | |
| Date | 28th November 1929 guessed | |
| -2- may in time burn out the cutout shunt coil. It occurs momentarily when switching off charge, with the above arrangement, and the switch not only breaks the normal armature current but a moderate field current as well. Of the remaining arrangements, the first in the above report, having the cutout on the armature side and field break first, has the same disadvantages as the foregoing in regard to failure of No.1 fuse, while when switching off charge there is a rather heavy spark at the cutout due to the considerable reverse current reached before the points have time to separate. The fourth case, described with cutout on the field side and armature break first, involves heavy sparking at the cutout points owing to reverse battery current in the field circuit. The arrangement standardised, therefore, is the best all round as the switchbox has only to break a normal field current, whilst the cutout conditions are almost as good as could be obtained by imposing the severest switchbox conditions. RJA. | ||