The percentage impedance of a 100 kVA, 11 kV/400V, delta/wye, 50 Hz transformer is 4.5%. For the circulation of half the full load current during short circuit test, with low voltage terminals shorted, the applied voltage on the high voltage side will be __________.

A differentially compounded d.c. motor with interpoles and with brushes on the neutral axis is to be driven as a generator in the same direction with the same polarity of the terminal voltage. It will then

Supply to one terminal of a $$\triangle$$ - Y connected three-phase core type transformer which is on no-load, fails. Assuming magnetic circuit symmetry, voltages on the secondary side will be:

A synchronous motor on load draws a current at a leading power factor angle $$\phi$$. If the internal power factor angle – which is the phase angle between the excitation e.m.f. and the current in the time phasor diagram is $$\psi$$, then the air gap excitation m.m.f lags the armature m.m.f by