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.

Previous Post Next Post