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Traditional and Electronic Current Transformers Theory Testing Chapter | 10 111
FIGURE 10.7 How to read the current transformer (CT) class for measuring and protection CTs.
FIGURE 10.8 Current transformer in schematic diagrams.
10.4.3 Current Transformer Open Circuited Secondary Winding
The secondary winding of the CT should never be left open-circuited whilst
the primary current continues to flow. In these circumstances, only the pri-
mary current is active and a peak high voltage appears at the secondary out-
put terminals. This situation is dangerous and can result in the breakdown of
the secondary circuit insulation of the CT (see also Fig. 10.8).
Equivalent CT accuracy ratings are shown in Table 10.3.
