GATE 2020 EE – Question 58
Windings 'A', 'B' and 'C' have 20 turns each and are wound on the same iron core as shown, along with winding 'X' which has 2 turns. The figure shows the sense (clockwise/anti-clockwise) of each of the windings only and does not reflect the exact number of turns. If windings 'A', 'B' and 'C' are supplied with balanced 3-phase voltages at 50 Hz and there is no core saturation, the no-load RMS voltage (in V, rounded off to 2 decimal places) across winding 'X' is ________.
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Correct answer: 0
Explanation
Balanced three-phase voltages on equal windings produce fluxes whose phasor sum is zero, $\phi_A+\phi_B+\phi_C=0$. Winding $X$ links the combined flux of the common path, so its induced voltage is zero.