For a 1.8o,2-phase bipolar stepper motor,the stepping rate is 100 steps/second.The rotational speed of the motor in rpm is

1.  15

2.  30

3.  60

4.  90

4
Correct Answer :

30

Explanation :
No Explanation available for this question

A 8 pole,DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each.its flux per pole is 0.06Wb,the machine is running at 250rpm.The induced armature voltage is

1.  96 V

2.  192 V

3.  384 V

4.  768 V

4
Correct Answer :

384 V

Explanation :
No Explanation available for this question

A 400V,50 Kva,0.8pf leading -connected,50Hz synchronous machine has a synchronous reactance of 2Ω and negligible armature resistance.The friction and windage losses are 2kW and the core loss is 0.8kW.The shaft is supplying 9kW load at a power factor of 0.8 leading.The line current drawn is

1.  12.29 A

2.  16.24 A

3.  21.29 A

4.  36.88 A

4
Correct Answer :

21.29 A

Explanation :
No Explanation available for this question

A 500MW 3-phase Y-connected synchronous generator has a rated voltage of 21.5kV at 0.85pf.the line current when operating at full load rated conditions will be

1.  13.43 kA

2.  15.79 kA

3.  23.25 kA

4.  23.25 kA

4
Correct Answer :

15.79 kA

Explanation :
No Explanation available for this question

A 800kV transmission line is having per phase line inductance of 1.1 mH/km and per phase line capacitance of 11.68 nF/km.Ignoring the length of the line its ideal power transfer capability in MW is

1.  1204 MW

2.  1504 MW

3.  82085 MW

4.  2606 MW

4
Correct Answer :

82085 MW

Explanation :
No Explanation available for this question

A 110 kV,single core coaxial,XLPE insulated power cable delivering power at 50 Hz,has a capacitance of 125 nF/km.if the dielectric loss tangent of XLPE is 2×10-4,then the dielectric power loss in this cable in W/km is

1.  5.0

2.  31.7

3.  37.8

4.  189.0

4
Correct Answer :

189.0

Explanation :
No Explanation available for this question

A lightning stroke discharges impulse current of 10 kA on a 400 kV transmission line having surge impedance of 250 Ω.The magniyude of transient over-voltage travelling waves in either direction assuming equal distribution from the point of lightning strike will be

1.  1250 kV

2.  1650 kV

3.  2500 kV

4.  2900 kV

4
Correct Answer :

1250 kV

Explanation :
No Explanation available for this question

The generalized circuit constants of a 3-phase,220 kV rated voltage,medium length transmission line are A=D=0.936+j0.016=0.9360.98o B=33.5+j138=142.076.4OΩ C=(-5.18+j914)×10-6Ω If the load at te receiving end is 50 MW at 220kV with a power factor of 0.9 lagging,then magnitude of line sending end voltage should be

1.  133.23 kV

2.  220.00 kV

3.  230.78 kV

4.  246.30 kV

4
Correct Answer :

230.78 kV

Explanation :
No Explanation available for this question

A new generator having Eg=1.4 30o pu [equivalent to (1.212+j0.70)pu] and synchronous reactance ‘Xs’ of 1.0pu on the system base,is to be connected to a bus having voltage V1 in the existing power system.this existing power system can be represented by Thevenins voltage Eth=0.90o pu in series with Thevenins impedance Zth=0.2590o pu.The magnitude of the bus voltage V1 of the system in pu will be

1.  0.990

2.  0.973

3.  0.963

4.  0.900

4
Correct Answer :

0.973

Explanation :
No Explanation available for this question

A 3-phase generator rated at 110 MVA,11 Kv is connected through circuit breakers to a transformer.The generator is having direct axis sub-transient reactance Xnd =19% transient reactance Xnd=26% and synchronous reactance=130%.The generator is operating at no load and rated voltage.when a three phase short circuit fault occurs between the breakers and the transformer.The magnitude of initial symmetrical rms current in the breakers will be

1.  4.44 kA

2.  22.20 Ka

3.  30.39 kA

4.  38.45 kA

4
Correct Answer :

30.39 kA

Explanation :
No Explanation available for this question

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