Vanguard EZCT-2000B - Manual (Page 112)

EZCT-2000B USER’S MANUAL REV 1
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Figure 25 shows a typical connection of a CT mounted on the primary bushing of a single phase
transformer. When the voltage V1 is introduced to the CT's secondary winding, there is an
induced voltage (V3) on the primary winding of this single phase transformer. Since the only
access to the transformer is between terminals H1-H0, The V3 voltage will be included and the
turns-ratio will be:
Ratio=
( )
Figure 25
Ideally, we would like to eliminate the V3 voltage and only see the V2 voltage. If the induced V3
voltage on the transformer winding cannot be eliminated, the turns-ratio measured will be
wrong!