The current transformer

The current transformer, although mentioned but briefly in electrical literature, is one of the most indispensable of meter auxiliaries. By means of it currents of any magnitude may be measured with accuracy with the smallest of instruments. It enables us to use ammeters and wattmeters in circuits of the highest voltages. By the use of current transformers of different ratios we can use meters of the same size and capacity in circuits of widely varying power and voltage, thereby greatly facilitating the calibration and maintenance of the instruments.