The power transformer can be termed as a constant

(a) voltage device.
(b) current device.
(c) power device.
(d) main flux device.

Answer
(d) main flux device.

Explanation:
  • The power transformer is a constant flux device because it follows Lenz's law, for every change in flux density caused by loading on secondary it will draw the magnetizing current proportionately from primary. So, the net flux in the core is always constant.
  • A transformer is a static device that transfers power from one circuit to another circuit without a change in frequency.
  • Generally, the winding which is connected to the supply is called as a primary winding and the winding on which load connected is called as a secondary winding.
  • In the transformer, two windings are electrically isolated but magnetically coupled. Hence the transformer is a coupled circuit.
  • The transformer is a singly excited device since it requires only one external voltage source to energize any number of windings placed on its core.
  • The transformer can be treated as a phase-shifting device since it offers a displacement of approx 1800 between two circuits.
  • As the amount of flux in the transformer core is constant irrespective of power transfer, it can be treated as a "Constant flux device".
  • The transformer is a negative feedback circuit because it satisfies 'Lenz's law'.




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