The transformer draws the current when its secondary winding is open.

A. Full load primary current
B. Full load secondary current
C. No-load primary current
D. No-load secondary current

Answer: C

Explanation:

• The secondary side of a current transformer should never be kept in open condition because, when kept open, there is a very high voltage found across the secondary side. 
• This high voltage causes a high magnetizing current to build up on the secondary side which in turn causes high flux and makes the core to saturate. 
• When the secondary winding of a current transformer is open-circuited with the primary winding energized, the large voltage may act as safety hazard for the operators and many even rupture the insulation.
• The secondary winding of the current transformer is always kept closed because if it open-circuited, the current transformer would develop an extremely high voltage across the secondary terminals. 
• It may lead to damage to the transformer insulation as well as arcing across the terminal.

For More Transformer MCQs (Set of 400 Most Asked MCQs)

Transformer MCQS  PART-01

Transformer MCQS  PART-02

Transformer MCQS  PART-03

Transformer MCQS  PART-04

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Transformer MCQS  PART-06

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Transformer MCQS  PART-08

Transformer MCQS  PART-09