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Information for the safe operation of current transformers

Operation Conditions for Current Transformers
Illustration

Operation Conditions for Current Transformers

  1. When the secondary terminals are connected to the measuring or protection devices, one of the terminals should be earthed for safety as seen in Figure CT-1.
  2. The secondary circuit of a current transformer must not be operated with an open-circuit.
  3. The secondary winding of a current transformer which will not be used must always be short-circuited and earthed as seen in Figure CT-2.
  4. For the transformer with reconnectable and/or tapped secondaries, unused terminals must be left open as seen in Figure CT-3.
  5. The current transformers which have capacitive divider tap (Ck) must be connected to the indicator. If the tap will not be used then it must be earthed as seen in Figure CT-4.