Answer / dinesh chaudhary

core losses are of two types i.e. hysteresis & eddy current
losse & hysteresis losses are directly proportional to the
frequency & eddy current losses are directly proportional
to the square of the frequency so, the losses will increase
that's why we cant use iron core transformer in high
frequency applications.

Answer / zohaib

iron core losses are directly proportional to frequency , greater frequency means greater iron core losses

Answer / dipankar

i think induced emf~phi.f, where phi=flux, and f=frequency.
to get a certain amount of induced emf for higher frequency
phi should have to be much lower value, and the required
iron core material should be of very high value, as for
lower flux value the flux density should be decreased and
required volume of the core for lower value of flux should
be increased, which is very undesirable for some
application like in airplane etc.Thats why we use air cored
transf. in place of iron cored transf. in high f.

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