# Assumptions in a ideal transformer [closed]

In a ideal transformer we assumed that there is no resistance in windings. Then why there is no infinite current in windings?

## closed as unclear what you're asking by winny, Lior Bilia, TonyM, Daniel Grillo, ChupacabrasDec 14 '17 at 7:59

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If you apply DC voltage (f = 0) to the windings, the reactance of the winding (inductor) will be zero due to $X_L = 2 \pi \ f \ L$ and thus the current will be infinite.
However, if you apply AC voltage (f ≠ 0), the source will see a non-zero reactance (again, $X_L = 2 \pi \ f \ L$) thus a finite-current of $i_p = V_s / X_L$ will flow through the winding.