Why is power factor of a transformer is poor at no load?

As we all know that transformer has two windings which is works in mutual induction.In case of no load, when the transformer is operating at no load,the secondary winding is open circuited, which means there is no load on the secondary side of the transformer and, therefore current in the secondary will be zero, while primary winding carries a small current I called no load current which is 2 t0o 10% of the rated current.
                                           
              In case there is some loading in the transformer secondary winding, some more current will be drawn from the source to compensate the demagnetizing effect of secondary current. So now net primary current would contain `NO LOAD CURRENT + EXTRA COMPENSATING CURRENT`.
And that would shift the net current phasor more towards the voltage axis and would result in the increment of the power factor.

   The same thing can be understood by the phasor diagram-

- First phasor is at no loading condition where Ip=Io and
   in the second phasor diagram Ip=Io+11 and it is simple that
   phase angle of first primary current is more than that of the
    second one.


Why is power factor of a transformer is poor at no load? Why is power factor of a transformer is poor at no load? Reviewed by Yugank Rawat on 11:51 PM Rating: 5

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