. Journal of electricity, power, and gas . the power in a three-wire direct current circuit, with this type of instru-ment. The alternating current meter of this type isshown diagramatically in Fig. 63. As will be noted, the armature circuit is in shunt with the source ofsupply in this case, as was above mentioned, ratherthan in series as is the case with the direct currenttype. The small potential transformer, N, has itsprimary, PT, connected across the line and inducesthrough its secondary, MS, a current of high amperageand very low This current flows directlythrough the armature as i
. Journal of electricity, power, and gas . the power in a three-wire direct current circuit, with this type of instru-ment. The alternating current meter of this type isshown diagramatically in Fig. 63. As will be noted, the armature circuit is in shunt with the source ofsupply in this case, as was above mentioned, ratherthan in series as is the case with the direct currenttype. The small potential transformer, N, has itsprimary, PT, connected across the line and inducesthrough its secondary, MS, a current of high amperageand very low This current flows directlythrough the armature as is shown. The actual valueof this secondary current is between 12 and 20 amperesat an of approximately volt. The trans-former also has an auxiliary secondary winding, terminals of which are connected through thevariable resistance, RR, t(i the light load adjustingcoil, J, which is wound on the same core with the seriesfield coils, FC. By moving the slider. K, along theresistance the compensating effect of the light load. The full load adjustment in the Sangamo meter isquite different from the usual practice, in that thedamping effect of the retarding magnets is varied byshunting more or less of the magnetic lines througha soft iron disc, H (Figs. 62 and 63), which is placeddirectly above the magnet system, rather than bymoving the magnets themselves. This soft iron discis movable in a vertical direction as shown ; by bring-ing it in close proximity of the magnets, it weakenstheir effect, thereby causing the meter to run faster. The Ampere-Hour Meter. The Sangamo ampere-hour meter, is now beingused quite frequently in connection with thecharging and discharging of storage batteries. Storagebatteries are rated on their ampere-hour capacity, andit will therefore be seen that an instrument which willindicate the amount of current that has been stored the amount of current remaining in a battery is a April 16. 1910] JOURNAL OF ELECTRICITY, POWER AND GAS 351 v
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Keywords: ., bookcentury1800, bookdecade1890, bookidjo, booksubjectelectricity
