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 an electrical system's reliability concerning the ignition apparatus, ballast resistance, and a relay switch.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan043 | |
| Date | 8th October 1926 guessed | |
| -4- Contd. the same order as that of the ignition apparatus in respect of its ballast resistance. Further than this, it is to be noted that the functioning of certain other parts of the electrical system, i.e. if this apparatus does get out of order, except in one particular way, it does not prevent the system from functioning. If the switch sticks on contact we have exactly the system which we have at present. If the switch sticks off contact, a very unlikely case, we have the system which we have at present but with reduced charge. The only vital element of unreliability would appear to be that due to breakage of the continuity of the ballast resistance which is inserted into the field circuit. Should such discontinuity occur this switch will go on and off contact alternately and flashing at the points will be produced, the cutout going in and out of contact at the same time. But it is no more likely to occur, carrying as it would, approximately the same current, than in the case of the similar ballast resistance on the ignition system. Altogether it will be seen that in adding this other unit we are adding quite a small proportional amount of possible unreliability. As regards the gain in better functioning of the system, this relay switch is definitely arranged in such a way that it requires considerably more ampere turns of excitation to open the switch than the amount to which these ampere turns must be reduced again to allow the switch to close. There are two excitation coils on the magnetic core Contd. | ||