The Automobile Storage Battery; Its Care and Repair (Paperback)

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. 1918 Excerpt: ...reactance being provided in the auto-transformer to accomplish the desired results. A proper proportion of reactance may be made to stop the action of the rectifier when the current falls to a certain value. This arrangement is particularly useful in connection with storage battery charging. The resistance "R" connected in series with the starting electrode "C," as shown in Figure 65, is to prevent an excessive current passing through the circuit when the tube is tilted for starting. The temperature of a tube must never be allowed to rise too high as the life of the tube is greatly reduced. Some of the larger tubes are immersed in oil to facilitate cooling. The vacuum in the tube may be tested by removing the tube from its supports and shaking it, if the vacuum is good, the mercury will give out a metallic sound. If the tube is dirty on the inside and there is a tendency for the mercury to stick to the sides, the vacuum is poor. An average life of over 600 hours is claimed for the sizes commonly used in charging the batteries in electric automobiles and in some cases a useful life of 5,000 hours has been obtained. The average life of small tubes used in charging ignition batteries is much greater. The efficiency of the rectifier varies with the voltage used on the direct-current side, as there is always a drop in voltage through the mercury vapor, which is practically independent of the current used. For rectifiers of 30 to 50 ampere capacity, the drop in voltage across the rectifier terminals is equal to about 15 volts. The lower the direct-current voltage therefore, the greater the percentage of loss. This loss is in addition to the losses in the auto-transformer and brings the average efficiency down to 75 or 80 percent for a direct c...