. Journal of electricity, power, and gas . typical calibration curve of agood current transformer, and Fig. loi shows the cali-bration curve of a standard induction watthour two curves are combined as shown in Fig. 102,the resultant curve, B, being the resultant calibrationcurve of the meter when used in connection with thetransformer. It will be seen that if the meter is ad-justed so that it will be a little slow on full load (about per cent), and if the light load adjustment is setso that the meter will be slightly fast (about percent) on 10 per cent load, the resultant c
. Journal of electricity, power, and gas . typical calibration curve of agood current transformer, and Fig. loi shows the cali-bration curve of a standard induction watthour two curves are combined as shown in Fig. 102,the resultant curve, B, being the resultant calibrationcurve of the meter when used in connection with thetransformer. It will be seen that if the meter is ad-justed so that it will be a little slow on full load (about per cent), and if the light load adjustment is setso that the meter will be slightly fast (about percent) on 10 per cent load, the resultant curve will bemore nearly correct, and when a high degree ofaccuracy is required, this is recommended, the amountof such adjustment being determined by referring tothe calibration curve of the transformer with whichthe meter is to be used. It should be remembered that a current trans-former must always have a load on its secondary side;if the meter or instrument with which it is beingused should be disconnected while current is still on the. primary, the transformer should either be disconnectedfrom the line, or else have its secondary the secondary is left open-circuited there will beno counter magneto-motive force from the secondary,consequently the magnetic flux will increase to sucha degree that it will cause the iron core to becomeoverheated to an extent that may injure the trans-former. The load carried by potential transformers isconstant, and if the load is light, the error in thetransformer ratio will be very small. The of the potential transformer leads the primary
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Keywords: ., bookcentury1800, bookdecade1890, bookidjo, booksubjectelectricity
