A three-phase squirrel cage induction motor has a starting torque of 150 % and a maximum torque of 300 % with respect to rated torque at rated voltage and rated frequency. Neglect the stator resistance and rotational losses. The value of slip for maximum torque is

1.  13.48 %

2.  16.24 %

3.  18.92 %

4.  26.79 %

View Answer  
4
Correct Answer :

26.79 \%


Explanation :
No Explanation available for this question

The matrix A given below is the node incidence matrix of a network. The columns correspond to branches of the network while the rows correspond to nodes. Let V = [v1 v2 ... v6]T denote the vector of branch voltages while I = [i1 i2.... i6]T that of branch currents. The vector E = [e1 e2 e3 e4]T denotes the vector of node voltages relative to a common ground. Which of the following statements is true

1.  The equations v1 - v2 + v3 = 0, v3 + v4 - v5 = 0 are KVL equations for the network for some loops

2.  The equations v1 - v3 - v6 = 0, v4 + v5 - v6 = 0 are KVL equations for the network for some loops

3.  E = AV

4.  AV = 0 are KVL equations for the network

View Answer  
4
Correct Answer :

E = AV


Explanation :
No Explanation available for this question

An isolated 50 Hz synchronous generator is rated at 15 MW which is also the maximum continuous power limit of its prime mover. It is equipped with a speed governor with 5% droop. Initially, the generator is feeding three loads of 4 MW each at 50 Hz. One of these loads is programmed to trip permanently if the frequency falls below 48 Hz. If an additional load of 3.5 MW is connected then the frequency will settle down to

1.  49.417 Hz

2.  49.917 Hz

3.  50.083 Hz

4.  50.583 Hz

View Answer  
4
Correct Answer :

50.083 Hz


Explanation :
No Explanation available for this question

Which one of the following statements regarding the INT (interrupt) and the BRQ (but request) pins in a CPU is true

1.  The BRQ pin is sampled after every instruction cycle, but the INT is sampled after every machine cycle

2.  Both INT and BRQ are sampled after every machine cycle

3.  The INT pin is sampled after every instruction cycle, but the BRQ is sampled after every machine cycle

4.  Both INT and BRQ are sampled after every instruction cycle

View Answer  
4
Correct Answer :

The BRQ pin is sampled after every instruction cycle, but the INT is sampled after every machine cycle


Explanation :
No Explanation available for this question

A bridge circuit is shown in the figure below. Which one of the sequences given below is most suitable for balancing the bridge

1.  First adjust R4 and then adjust R1

2.  First adjust R2 and then adjust R3

3.  First adjust R2 and then adjust R4

4.  First adjust R4 and then adjust R2

View Answer  
4
Correct Answer :

First adjust R4 and then adjust R1


Explanation :
No Explanation available for this question

If an autotransformer is used for reduced voltage starting to provide 1.5 per unit starting torque, the autotransformer ratio (%) should be

1.  57.77 %  

2.  72.56 %

3.  78.25 %

4.  81.33 %

View Answer  
4
Correct Answer :

78.25 \%


Explanation :
No Explanation available for this question

If a star-delta starter is used to start this induction motor, the per unit starting torque will be

1.  0.607

2.  0.816

3.  1.225

4.  1.616

View Answer  
4
Correct Answer :

0.816


Explanation :
No Explanation available for this question

If a starting torque of 0.5 per unit is required then the per unit starting current should be

1.  4.65

2.  3.75

3.  3.16

4.  2.13

View Answer  
4
Correct Answer :

3.16


Explanation :
No Explanation available for this question

The resistance R should be

1.  4.7 k

2.  470 ?

3.  47 ?

4.  4.7 ?

View Answer  
4
Correct Answer :

47 ?


Explanation :
No Explanation available for this question

The minimum approximate volt - second rating of the pulse transformer suitable for triggering the SCR should be : (volt - second rating is the maximum of product of the voltage and the width of the pulse that may be applied)

1.  2000 µV - s

2.  200 µV - s

3.  20 µV - s

4.  2.0 µV - s

View Answer  
4
Correct Answer :

2000 µV - s


Explanation :
No Explanation available for this question
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