| Show by G couglas sai droP editor of italio jve mi i clayed flayed n n aiming IWO 0 nd plew A high i voltage storage battery has boon been used by the radio laboratory of the bureau of standards for over four bears years and has given excellent service liany calls have been received for information regarding such batteries the particular batteries to be described are used to furnish plate current tor for a 11 generator of radio fre quency current the electron tube used Is elther a VT 2 or a type P or their equivalents the current for the first tube may range from 5 to 80 30 milliamperes while for the latter tube it may be milliamperes depending g on the plate voltage used it Is necessary that 9 constant current of small value be available elements the individual elements composing this battery are type LT chloride accumulators the following data are taken from a catalogue DI dichario Charit in amperes ampere alze 11 Z 1 of 01 number for type plata of 0 miss I 1 tire 6 urs hr 1 tire tin LT 1 3 16 V 25 2 f normal dimensions 0 of weight I 1 charge glass jar in lounda rate hate electro corn com amperui ampe so len leneth th width lyte at 1 t 1 1 16 15 the batteries were made up using twelve cells per row and four rows to the tray giving about volts when charged the illustration shows the arrangement as employed at present with one exception which will be mentioned inter wooden trays were made up of inch lumber measuring lla by 10 19 by 4 inches deep begs ega 1 inches long were placed at each corner Vertical I 1 supports 12 inches high were era fastened at ench each corner of the tray so alint hat the trays plight be built up in stacks it if desired thus occupying a minimum min linum of floor or table space the trays were given ghen two coats of black insulating varnish allowing plenty ot of time for drying between coats melted paraffin was poured into the troy tray and allowed to harden the glass jars the top of which had been dipped in paraffin for about an inch down the side aide were then put in place and one end of the tray blocked up about two inches more blore paraffin was poured in until it come came within about one inch of af the top at one end and about three inches from the top at the other end after the paraffin hardened and the tilting blocks were removed a sloping surface resulted which Is convenient for washing out any add acid or dirt A flared glass tube was put through the bottom of the tray at the lower end to drain off any water or add acid plates the ne plates for the battery come in pairs consisting of one positive end and one negative plate joined by a lead link the plates going in adjacent cells and being supported by the lead link the battery was made up in such buch a way that its terminals were at the opposite end from which the tray to la drained chemically pure sulphuric add acid Is diluted to bring the specific gravity to directions for mixing the electrolyte may be found in any handbook on storage batteries batt erlea the electrolyte to in the jara should come about one fourth inch above III the e top of tile the plates paraffin covers were made for the cells the majority of covers in use consist of one ong cover tor for each rov of cells alfe th epa paraffin raffin was poured into a wooden mold or trough about 1 by 38 inches forming a piece about one quarter inch thick while the cover was still warm it was removed from the mold and placed on top of the row of cells where it was w as pressed down and conformed to the tops of abe th elars jars end and lend lead links in the center above each ach jar a considerable depression was made and a small hole made for gases to escape this method gives a convex eito the under side of the cover go BO that the spray forming when tile the cell Is charging collects on the cover and forms droplets which are returned to lo the lie electrolyte As would be expected the covers have r reduced deduced the ridlon greatly in addition to keeping dust out of the cells when the batteries are on charge no spray or fumes isie are noticeable in the room ench each terminal of v ach battery comes out to the blade of a single pole double throw switch mounted on the bertl vertical cal of the tray the lower terminals terminal S of a all 1 I 1 pr y etive terminal fial switches arec are connected knect ed together the same being true me of the negative terminal switches by throwing all of the witches switches Cown ward the batteries batter leff are placed la in parallel el either ther tor for obtaining volts or for charging from the volt TO direct current mains the batteries ar art connected directly to the volt tolt mains through small fuses fu sea when charging the upper terminals of the switches are connected conn la in series positive to negative and have suitable binding posts attached to each pair of switch terminals for the wires from the radio frequency generator dy by a suitable throwing of switches any voltage from to OW COO may be obtained with these batteries tho the voltage obtained of course depends on the number of trays when operating tb the e larger electron tube three of the batteries may be in use while the other three are being charged quite a number of bf these batteries have been used by the radio laboratory of the bureau of standards and they have been entirely satisfactory tor for supplying a small constant current such as Is necessary for electron tube generators era tors to obtain best results the batteries must be given some attention to see that the jars are kept filled with distilled water to a height somewhat above the top of the plates and are charged from time thoe to time now how often the batteries are charged depends on how bow much they are used it Is preferable to charge them oftener and keep them well charged than to use them to the limit charging them only at wide intervals or when nearly run down the trays should be washed out once in two or three weeks with clean water to remove any collected acid or dirt maintenance As As has been previously stated storage batteries of this general type using same type of element have been in use in the radio laboratory for over tour four years W no definite data have been bollek colle to show the useful life of such lil high afi voltage batteries some very conservative estimates may be given tho the life of such batteries Is greatly influenced by the care afforded them good care includes keeping the jars and wax tree free of acid spray and dust keeping jars properly tilled filled keeping within the proper ampere hour charge and discharge rate and it if batteries are not normally used at the specified discharge rate they should be exercised about every two weeks by discharging through gha a resistance at the proper discharge rate and then recharged batteries of this type which have been given proper attention have been in use for over four years and are yet quite serviceable others have gono gone to ruin in six months for formant want of care radio news newe |
