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).
The interpretation of voltage readings in a secondary cell using a cadmium electrode.
| Identifier | ExFiles\Box 44\5\ Scan007 | |
| Date | 2nd September 1925 | |
| X.4049 EFC1/T2.9.25. RE CADMIUM ELECTRODE. On a secondary cell discharged down to 1.80 volts, and discharging, but otherwise in good condition, the positive plate should be 2.05 volts positive to the Cadmium electrode and the negative should be .25 volts positive to this electrode. The Cadmium electrode is the negative datum for the instrument and both plates are positive to it. As a rule for the interpretations of the instrument used with the Cadmium electrode, it should b-e remembered that the positives should be as positive as possible to the Cadmium electrode, and the extent by which the reading falls short of 2.05 is a measure of the weakness of the positive element. Also that the negative should be as little positive as possible to the Cadmium electrode, and the extent to which the reading exceeds .25 is a measure of the weakness of the negative element. When a cell shows a terminal P.D. greater than 1.80 volts, due to being in a higher state of charge and/or not discharging, the reading of the positive element should be more than 2.05, and that of the negative element less than .25. If, in this condition, it is judged that one of these readings shows too little difference from the limit, even though it be within it, it still may be | ||