Can a 50 Hz transformer be used for 25 Hz, if the input

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Can a 50 Hz transformer be used for 25 Hz, if the input voltage is maintained constant at the rated vale corresponding to 50 Hz?

1. Yes. Since the voltage is constant, current levels will not changed.
2. No. Flux will be doubled which will drive the care to excessive saturation
3. No. Owing to decreased reactance of transformer, input current will be doubled atload
4. Yes. At constant voltage, insulation will not be overstressed.

Correct Option: B

V = √2 n ƒB_mA₁N
This expression shows that if V is unchanged and ƒ gets reduced to half, B_m will have to get doubled, thereby driving the core into saturation.