1
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
The ac bridge shown in the figure is used to measure the impedance $$Z.$$ If the bridge is balanced for oscillator frequency $$f=2$$ $$kHz$$, then the impedance $$Z$$ will be GATE EE 2008 Electrical and Electronics Measurement - Measurement of Resistance and A.C Bridges Question 5 English
A
$$\left( {260 + j0} \right)\,\Omega $$
B
$$\left( {0 + j200} \right)\,\Omega $$
C
$$\left( {260 - j200} \right)\,\Omega $$
D
$$\left( {260 + j200} \right)\,\Omega $$
2
GATE EE 2008
MCQ (Single Correct Answer)
+1
-0.3
In a stepper motor, the detent torque means
A
minimum of the static torque with phase winding excited.
B
maximum of the static torque with phase winding excited.
C
minimum of the static torque with phase winding unexcited
D
maximum of the static torque with the phase winding unexcited
3
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
A $$400$$ $$V,$$ $$50$$ $$Hz,$$ $$30$$ $$hp,$$ three-phase induction motor is drawing $$50$$ A current at $$0.8$$ power factor lagging. The stator and rotor copper losses are $$1.5kW$$ and $$900$$ $$W$$ respectively. The friction and windage losses are $$1050$$ $$W$$ and the core losses are $$1200$$ $$W.$$ The air-gap power of the motor will be
A
$$23.06$$ $$kW$$
B
$$24.11$$ $$kW$$
C
$$25.01$$ $$kW$$
D
$$26.21$$ $$kW$$
4
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
A $$400$$ $$V,$$ $$50$$ $$Hz$$, $$4$$ pole, $$1400$$ $$rpm$$, star connected squirrel cage induction motor has the following parameters referred to the stator:
$$R = 1.0\,\Omega ,{X_s} = X{'_r} = 1.5\,\Omega $$ Neglect stator resistance and core and rotational losses of the motor. The motor is controlled from a $$3$$-phase voltage source inverter with constant $$V/f$$ control. The stator line-to-line voltage $$(rms)$$ and frequency to obtain the maximum torque at starting will be:
A
$$20.6\,V,\,\,2.7\,Hz$$
B
$$133.3\,V,\,\,16.7\,Hz$$
C
$$266.6\,V,\,\,33.3\,Hz$$
D
$$323.3\,V,\,\,40.3\,Hz$$