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Polarity marks designate the relative instantaneous directions of the currents. At the same instant of
time that the primary current is entering the primary terminal the corresponding secondary current is
leaving the similarly marked secondary terminal. A CT under test is supposed to have correct polarity if
instantaneous current direction for primary and secondary current is opposite to each other.
Same connection settings as for Ratio test can be used for performing Polarity test. The two non polarity
marks are shorted together internally and potential is measured across the two polarity mark points. For
correct polarity, primary winding voltage will be in-phase with secondary winding voltage, with a phase
angle difference of zero or close to that. A CT with reverse polarity would read the sum of the two
primary and secondary voltages indicating a phase difference of approximately 180 degrees. MVCT
performs this test in automated fashion and display the result as either Polarity correct or incorrect.
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