GATE EE 2016 Question Paper (07-Feb-2016) (Shift 2)

The power consumption of an industry is $500kVA,at0.8p.f.$ lagging. A synchronous motor is added to raise the power factor of the industry to unity. If the power intake of the motor is $100kW$, the $p.f.$ of the motor is _____________

The flux linkage $\left(\lambda \right)$ and current $\left(i\right)$ relation for an electromagnetic system is $\lambda =\left(\sqrt{i}\right)/g$ when $I=2A$ and g(air-gap length) $=10cm$, the magnitude of mechanical force on the moving part, in $N$, is ________.

The starting line current of a $415V,3-phase$, delta connected induction motor is $120A$, when the rated voltage is applied to its stator winding. The starting line current at a reduced voltage of $110V$, in ampere, is _________.

A single-phase, $2kVA,100/200V$ transformer is reconnected as an auto-transformer such that its kVA rating is maximum. The new rating, in $kVA$, is ______.

A full-bridge converter supplying an RLE load is shown in figure. The firing angle of the bridge converter is 120º. The supply voltage $v_m\left(t\right)=200\pi sin\left(100\pi t\right)V$, $R=20\Omega ,E=800V$. The inductor L is large enough to make the output current $I_L$ a smooth dc current. Switches are lossless. The real power fed back to the source, in $kW$, is __________.