This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ...case until it has become a charge in the opposite direction. Reversed plates are shown in Figure 96. (7) Local action on some portions of some or all of the plates in a cell will result in over-discharge of these plates because of the continued activity of the small local cells thus formed. (8) Some kinds of ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ...case until it has become a charge in the opposite direction. Reversed plates are shown in Figure 96. (7) Local action on some portions of some or all of the plates in a cell will result in over-discharge of these plates because of the continued activity of the small local cells thus formed. (8) Some kinds of impurities in a cell will bring about over-discharge through the continual transfer of energy that takes place between the plates of opposite polarity. (9) Exposure of the negative plates to the air will cause rapid oxidation of the sponge lead, followed by hardening and final sulphation of these plates. (10) Failure to keep the cells filled with liquid above the tops of the plates will allow the exposed portions of the plates to become covered with a hard coating of sulphate, as shown in Figure 97. Overheating and specific gravity above 1.300 for any length of time will increase the formation of sulphate after it has once started to collect on the surfaces of the plates. It will also be found that the plates of an idle battery will gradually sulphate to some extent, even though the battery is in a fully charged condition. Results of Over-Sulphation.--Because the uneombined sulphate is an electrical insulator, the portions of the plates thus affected are shut off from the action of the charging current and are also inactive during discharge for the same reason. This results in a serious loss of capacity in the battery and a reduction of its efficiency and life. The excess sulphate causes a high internal resistance with the effect of increasing the difficulty of charging and reducing the current available on discharge. Because of the reduction in effective active surface of plates which are over-sulphated, and the consequent overloading of...
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