GATE EE 2015 Question Paper (07-Feb-2015) (Shift 2)

A shunt – connected DC motor operates at its rated terminal voltage. Its no – load sped is 200 radians/second. At its rated torque of 500 Nm, its speed is 180 radian/second, The motor is used to directly drive a load whose load torque T${}_L$ depends on its rotational speed (in radian/second), such that $T_L=2.78\times {\omega }_T$. Neglecting rotational losses, the steady – state speed (in radian/second) of the motor, when it drives this load is_____________

The figure shows the per-phase equivalent circuit of a two-pole three-phase induction motor operating at 50 Hz. The “air-gap” voltage, $V_g$ across the magnetizing inductance, is 210 V rms, and the slip, is 0.05. The torque (in Nm) produced by the motor is _______.

A 4 – pole, separately excited, wave wound DC machine with negligible armature resistance is rated for 230 V and 5 kW at a speed if 1200 rpm. If the same armature coils are reconnected to forms a lap winding, what is the rated voltage (in volts) and power (in kW) respectively at 1200 rpm of the reconnected machine if the field circuit is left unchanged?

An open loop control system results in a response of $e^{-2t}\left(sin5t+cos5t\right)$ for a unit impulse. The DC gain of the control system is_______________

Nyquist plots of two function $G_1\left(s\right)$ and $G_2\left(s\right)$ are shown in figure.



Nyquist plot of the product of $G_1\left(s\right)$ and $G_2\left(s\right)$ is