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).
Examination report comparing the 7-plate and 9-plate sections of a P & R 3A battery.
| Identifier | WestWitteringFiles\Q\February1927-March1927\ 30 | |
| Date | 9th February 1927 | |
| JC.72. RE EXAMINATION OF P & R 3A. BATTERY. Two cells of this battery have been opened up for examination, one having the 9-plate sections and the other the 7-plate sections. General Condition. Cell to cell connecting links were clean and sound. The sealing compound was badly cracked due to the positive plates swelling and tending to force it up. These plates stood about 3/8" above the negative plates at the top. The cracks referred to in JC.69 2.2.27 were worse in the case of the 9-plate section than in the 7-plate. The leakage current at 4 volts due to these was measured with a voltmeter when all the links were sawn through. The 9-plate section shewed 3 m.a. leakage current and the 7-plate section shewed 1 m.a. An equal amount of sediment had collected in each cell which reached up to the plates and caused a partial short. Condition of the 7-plate section. The negative plates were good. The positive plates were very weak, and were badly broken in removing them from the case, but the paste had been retained excellently. The wood separators were in good condition, a few only being slightly punctured. The ebonite separators were practically all eaten away leaving just the wood. Condition of 9-plate section. The negative and positive plates were in a similar condition to the 7-plate, only that the negative plates appeared to have been lengthened by another piece of plate being burnt on at the bottom. In one case a crack has occurred at this point. The wood separators were worse being badly punctured in comparison with the 7-plate, but the ebonite separators were better, only being slightly eaten through. The decision arrived at is that there is little to choose between the two types, the only difference being that the 9-plates swell more and cause bad distortion of the cell case, than do the 7-plate section. EFC/G.Johnson. | ||