1
GATE EE 2012
+2
-0.6
The locked rotor current in a 3-phase, star connected 15 kW, 4-pole, 230 V, 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 V, 57 Hz supply is
A
58.5 A
B
45.0 A
C
42.7 A
D
55.6 A
2
GATE EE 2011
+2
-0.6
A three-phase 440V, 6 pole, 50Hz, squirrel cage induction motor is running at a slip of 5%. The speed of stator magnetic field to rotor magnetic field and speed of rotor with respect to stator magnetic field are
A
zero, 50 rpm
B
zero, 955 rpm
C
1000 rpm, -5 rpm
D
1000 rpm, 955 rpm
3
GATE EE 2009
+2
-0.6
A $$200$$ $$V,$$ $$50$$ $$Hz,$$ single-phase induction motor has the following connection diagram and winding orientations shown. $$MM'$$ is the axis of the main stator winding $$\left( {{M_1}{M_2}} \right)$$ and $$AA'$$ is that of the auxiliary winding $$\left( {{A_1}{A_2}} \right).$$ Directions of the winding axis indicate direction of flux when currents in the windings are in the directions shown. Parameters of each winding are indicated. When switch $$S$$ is closed, the motor
A
rotates clockwise
B
rotates anticlockwise
C
does not rotate
D
rotates momentarily and comes to a halt
4
GATE EE 2008
+2
-0.6
A $$230V,$$ $$50Hz,$$ $$4$$ pole, single phase induction motor is rotating in the clockwise (forward) direction at a speed of $$1425$$ $$rpm.$$ If the rotor resistance at standstill is $$7.8\,\,\Omega ,$$ then the effective rotor resistance in the backward branch of the equivalent circuit will be
A
$$2\Omega$$
B
$$4\Omega$$
C
$$78\Omega$$
D
$$156\Omega$$
EXAM MAP
Medical
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