CHARGING THE 112-VOLT ACCUMULATOR

Radio Record, Volume I, Issue 11, 30 September 1927, Page 14

CHARGING THE 112-VOLT ACCUMULATOR

AN A BATTERY CHARGER CAN BE USED

This is a small device that can be added to the 112-volt B accumulator that has already been described in this column. Its addition does not entail any removing of tubes or plates in the ease of a battery already constructed aud in working order. The device is a very efficient and reliable switching arrangement whereby the battery can be charged by any. A battery charger giving a voltage of about 20 or 24. The object is to do away with the use of a chemical rectifier, and utilise the quicker and more reliable double-wave valve charger, of which a number of good makes are available. ‘This will, encourage constructors and listeners to get the one charger, and Iet it be a good one; and one that will answer for both batteries. It should also be mentioned here that this attachment can be used in connection with any type of B_ battery, end has been applied to a bought battery of three units with uninterrupted success. The idea has been in use for a long period, lids stood the test oi time, and can be recommended. The principle made use of is that of charging in parallel and discharging in series, the change from one conuection to the other being made by the lifting of the ‘series’? connector, and substitution of the ‘parallel,’ or charging connector In order to give absolutely reliable contact that need .never go wrong, small mercury cups are used, aud the construction of these as directed will be quite a simple matter. These cups, twefty itt number, are placed through two rows of holes drilled in a piece of tin. ebonite 6} x 1} inclies, and which takes the place of the flat strip of wood above the front panel of thie battery. Wiring Diagram. As the wiring diagram is now ready, it will be explained first, and should be compared with the original diagram published. At the top is shown the battery of tubes, with a lead coming from the front and back tube of each row. A difference is now to be noted, for whereas a branch was originally taken from each positive tap to connect to the front end of the next row of tubes,. this short connection is now to be taken away, leaving the negatives unconuected. A wire from the corresponding mercury cup will later be soldered to the tag projecting above tliese uegative plates. ‘The two rows of mercury cups are shown below the tubes, the back row all negative and the front row all positive The positive end of each tube row is already connected to the tapping sockets on frout panel, and these sockets must now also be connected to the correspondiugly numbered mercury cup in the front row. It should be noted that

all cups except.the two end ones of each row are connected to the respective positive and negative ends of rows of tubes. An extra charging terminal is now placed above the one already supplied. The left-hand cups are connected to G socket and positive charging terminal and right-haud pair to 112-volt socket and negative charging terminal. The charger can be left permanently connected to these, as there is provision

in the connectors that only closes the circuit from the cups when charging is arranged for. In order to allow more room for connections behind the top of the front panel, it should be put down to the bottom of the side pieces when replacing, and the inch space at top filled up with a strip of wood. A narrow Strip can be screwed on bottom end of side pieces, front flush with bottom edge of panel, and holes drilled to take plugs when not in use. The Mercury Cup Panel. This, as already mentioned, is a piece of fin. ebonite 6$ by 1} inchies. Next week a fullsize templet of this will he given so that positions of holes to be drilled can be punched through the paper direct upon the ebonite. Space does not permit of the description being completed in this issue, so it will be concluded next week.