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Fig. 42.—Construction of Westing house Vibrator Type Alternating-Current Rectifier at A, and Wiring
Diagram Showing Operation at B.
it can be passed through the battery. Alternating current is that which flows first in one direction and immediately afterward in the reverse direction. When used in charging storage batteries some form of rectifier is essential. The rectifier may be a simple form, as shown at Fig. 43 A, which is intended to be coupled directly into a lighting circuit by screwing the plug attached to the flexible cord in the lamp socket. A rotary converter set, such as shown at B, or at Figs. 39 and 41, may also be used; in this the alternating current is depended on to run an electric motor, which drives the armature of a direct-current dynamo. The current to charge the battery is taken from the dynamo as it is suitable for the purpose, whereas that flowing through the motor cannot be used directly. V The view at Fig. 43 C shows a usual form of hydrometer syringe which is introduced into the vent hole of the storage battery, such as shown at Fig. 44, and enough electrolyte drawn out of the cell to determine its specific gravity. This is shown on the hydrometer scale, as indicated in the enlarged sections. A very useful appliance where considerable storage-battery work is done is shown at Fig. 45 A. This is a stand of simple form, designed to carry a carboy containing either acid, distilled water or electrolyte. In fact, it might be desirable to have three of these stands, which are inexpensive, one for each of the liquids mentioned. In many repair shops the replenishing of storage batteries is done in a wasteful manner, as the liquid is carried around in a bottle or old water pitcher and poured from that container into the battery, often without the use of a funnel. The chances of spilling are, of course, greater than if the liquids were carefully handled and more time than necessary is consumed in doing the work. The stand shown is about 5 feet high and is fitted with castors so it may be easily moved about the shop if necessary. For example, in taking care of electric vehicle batteries, it may be easier to move the carboy to the battery than to remove the heavy battery from the automobile. The container for the liquid is placed on top of the stand and the liquid is conveyed from it by a rubber tube. The rubber tube is attached to a glass tube extending down nearly to the bottom of the liquid. At the bottom
Fig. 43.-Devices Used in Charging and Caring for Storage Batteries. of the rubber tube an ordinary chemist's clip, which controls the flow of liquid, is placed. In order to start a flow of liquid it is necessary to blow into a bent glass vent tube, which is also inserted into the stopper. Once the rubber tube has become filled
Fig. 44.—Outlining Positions of Hydrometer in Electrolyte When
Cell is Discharged at A and When Cell is Charged at B. Method of Determining Electrolyte Level at C. How to Take Specific Gravity Reading Shown at B.
with liquid, merely opening the clip will allow the liquid to flow into the battery as desired.
In most communities the incandescent lighting circuit is used for charging batteries on account of the voltage of the power circuits being too high. The incandescent lighting circuit may be
any one of six forms. A direct current of either 110 or 220 volts used over short distances, either 220 or 410 volts on three-wire circuits over long distances, alternating current at a constant potential, usually 110 volts and in various polyphase systems. It might be stated that in the majority of instances house and garage lighting circuits furnish direct current of 110 volts. We will consider the devices used with the alternating form, one of which is