1. Synchronous motors are generally not self-starting because _____.
2. In case one phase of a three-phase synchronous motor is short-circuited the motor will
3. A pony motor is basically a ______.
4. A synchronous motor can develop synchronous torque ______.
5. A synchronous motor can be started by _______.
6. A three-phase synchronous motor will have ______.
7. Under which of the following conditions hunting of synchronous motor is likely to occur ?
8. When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected
9. When V is the applied voltage, then the breakdown torque of a synchronous motor varies as
10. The power developed by a synchronous motor will be maximum when the load angle is
11. A synchronous motor can be used as a synchronous capacitor when it is
12. A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased
13. Mostly, synchronous motors are of _______.
14. The synchronous motor is not inherently self-starting because _______.
15. As the load is applied to a synchronous motor, the motor takes more armature current because
16. Synchronous motor always runs at ______.
17. An over-excited synchronous motor takes ______.
18. The working of a synchronous motor is similar to ________.
19. The minimum armature current of the synchronous motor corresponds to operation at
20. In a synchronous motor, the magnitude of stator back e.m.f. £& depends on
21. If load (or torque) angle of a 4-pole synchronous motor is 6° electrical, its value in mechanical degrees is
22. For V-curves for a synchronous motor the graph is drawn between
23. The back e.m.f. of a synchronous motor depends on
24. A synchronous motor can operate at
25. In a synchronous motor which loss varies with load ?
26. A synchronous motor can be made self starting by providing
27. The oscillations in a synchronous motor can be damped out by
28. The shaft of synchronous motor is made of
29. When the field of a synchronous motor is under-excited, the power factor will be
30. The speed regulation of a synchronous motor is always
31. The percentage slip in case of a synchronous motor is
32. The operating speed of a synchronous motor can be changed to new fixed value by
33. A synchronous motor will always stop when
34. hunting in a synchronous motor takes place
35. When load on an over-excited or under excited synchronous motor is increased, rate of change of its armature current as compared with that of power factor is
36. The rotor copper losses, in a synchronous motor, are met by
37. The maximum power developed in a synchronous motor occurs at a coupling angle of
38. When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor
39. In which of the following motors the stator and rotor magnetic field rotate at the same speed ?
40. Synchronizing power of a synchronous machine is
41. Synchronous motors are
42. The standard full-load power factor ratings for synchronous motors are
43. A synchronous motor running with normal excitation adjusts to load increases essentially by increase in
44. A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because
45. A synchronous motor working at leading power factor can be used as
46. Slip rings are usually made of ______.
47. An over excited synchronous motor is used for
48. When the voltage applied to a synchronous motor is increased, which of the following will reduce ?
51. The efficiency of a properly designed synchronous motor will usually fall in range
52. To limit the operating temperature an electrical machine should have proper
53. Slip-rings in a synchronous motor carry
54. A synchronous machine with large air gap has
55. The armature current of the synchronous motor has higher values for
56. In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
57. The angle between the rotating stator flux and rotor poles is called _____ angle.
58. Which of the following methods is used to start a synchronous motor ?
59. When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop
60. An important advantage of a synchronous motor over wound round induction motor is that
61. The mechanical displacement of the rotor with respect to the stator, in polyphase multipolar synchronous motors running at full load, is of the order of
62. Power factor of a synchronous motor is unity when
63. Change of D.C. excitation of a synchronous motor changes
64. While starting a synchronous motor by induction motor action, field winding is usually
65. Which of the following motors will be used in electric clocks ?
66. If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor
67. A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will
68. While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
69. Armature of a synchronous machine is
70. If excitation of a synchronous motor running with a constant load is decreased from its normal value, ignoring effects of armature reaction, it leads to
71. When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way
72. Stability of a synchronous machine
73. The power factor of a synchronous motor is better than that of induction motor because
74. If in a synchronous motor, driving a given mechanical load and drawing current at a leading power factor from constant voltage supply its field excitation is increased, its power factor
75. A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because
76. If one-phase of a 3-phase synchronous motor is short-circuited, motor
77. If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then
78. In which of the following motors the stator and rotor fields rotate simultaneously ?
79. The speed of a synchronous motor
80. A rotory converter can also be run as a
81. The maximum speed variation in a 3-phase synchronous motor is
82. Which of the following resistances can be measured by conducting insulation resistance test on a synchronous motor ?
83. Due to which of the following reasons a synchronous motor fails to pull into synchronism after applying D.C. field current ?
84. In a synchronous motor, the maximum power developed depends on all of the following except
85. In a 3-phase synchronous motor, the negative phase sequence exists when the motor is
86. In a synchronous motor, damper windings are provided on
87. The induced e.m.f. in a synchronous motor working on leading power factor will be
88. The effect of increasing the load on a synchronous motor running with normal excitation is to
89. The net armature voltage of a synchronous motor is equal to the
90. The ratio of starting torque to running torque in a synchronous motor is
91. In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on
92. A 3-phase synchronous motor is running clockwise. If the direction of its field current is reversed
93. The magnitude of field flux in a 3-phase synchronous motor
94. The torque angle, in a synchronous motor, is the angle between
95. Hunting in a synchronous motor cannot be due to
96. By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ?
97. In a synchronous motor, V-curves represent relation between
98. In a 3-phase, 4-pole, 50 Hz synchronous motor, the frequency, pole number and load torque all are halved. The motor speed will be
99. A synchronous motor connected to infinite bus-bars has at constant full load, 100% excitation and unity power factor. On changing the excitation only, the armature current will have
100. Which of the following motors is non-self starting ?
2. In case one phase of a three-phase synchronous motor is short-circuited the motor will
3. A pony motor is basically a ______.
4. A synchronous motor can develop synchronous torque ______.
5. A synchronous motor can be started by _______.
6. A three-phase synchronous motor will have ______.
7. Under which of the following conditions hunting of synchronous motor is likely to occur ?
8. When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected
9. When V is the applied voltage, then the breakdown torque of a synchronous motor varies as
10. The power developed by a synchronous motor will be maximum when the load angle is
11. A synchronous motor can be used as a synchronous capacitor when it is
12. A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased
13. Mostly, synchronous motors are of _______.
14. The synchronous motor is not inherently self-starting because _______.
15. As the load is applied to a synchronous motor, the motor takes more armature current because
16. Synchronous motor always runs at ______.
17. An over-excited synchronous motor takes ______.
18. The working of a synchronous motor is similar to ________.
19. The minimum armature current of the synchronous motor corresponds to operation at
20. In a synchronous motor, the magnitude of stator back e.m.f. £& depends on
21. If load (or torque) angle of a 4-pole synchronous motor is 6° electrical, its value in mechanical degrees is
22. For V-curves for a synchronous motor the graph is drawn between
23. The back e.m.f. of a synchronous motor depends on
24. A synchronous motor can operate at
25. In a synchronous motor which loss varies with load ?
26. A synchronous motor can be made self starting by providing
27. The oscillations in a synchronous motor can be damped out by
28. The shaft of synchronous motor is made of
29. When the field of a synchronous motor is under-excited, the power factor will be
30. The speed regulation of a synchronous motor is always
31. The percentage slip in case of a synchronous motor is
32. The operating speed of a synchronous motor can be changed to new fixed value by
33. A synchronous motor will always stop when
34. hunting in a synchronous motor takes place
35. When load on an over-excited or under excited synchronous motor is increased, rate of change of its armature current as compared with that of power factor is
36. The rotor copper losses, in a synchronous motor, are met by
37. The maximum power developed in a synchronous motor occurs at a coupling angle of
38. When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor
39. In which of the following motors the stator and rotor magnetic field rotate at the same speed ?
40. Synchronizing power of a synchronous machine is
41. Synchronous motors are
42. The standard full-load power factor ratings for synchronous motors are
43. A synchronous motor running with normal excitation adjusts to load increases essentially by increase in
44. A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because
45. A synchronous motor working at leading power factor can be used as
46. Slip rings are usually made of ______.
47. An over excited synchronous motor is used for
48. When the voltage applied to a synchronous motor is increased, which of the following will reduce ?
51. The efficiency of a properly designed synchronous motor will usually fall in range
52. To limit the operating temperature an electrical machine should have proper
53. Slip-rings in a synchronous motor carry
54. A synchronous machine with large air gap has
55. The armature current of the synchronous motor has higher values for
56. In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
57. The angle between the rotating stator flux and rotor poles is called _____ angle.
58. Which of the following methods is used to start a synchronous motor ?
59. When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop
60. An important advantage of a synchronous motor over wound round induction motor is that
61. The mechanical displacement of the rotor with respect to the stator, in polyphase multipolar synchronous motors running at full load, is of the order of
62. Power factor of a synchronous motor is unity when
63. Change of D.C. excitation of a synchronous motor changes
64. While starting a synchronous motor by induction motor action, field winding is usually
65. Which of the following motors will be used in electric clocks ?
66. If in a synchronous motor, driving mechanical load and drawing current at lagging power factor from constant voltage supply, its field excitation is increased, then its power factor
67. A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will
68. While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
69. Armature of a synchronous machine is
70. If excitation of a synchronous motor running with a constant load is decreased from its normal value, ignoring effects of armature reaction, it leads to
71. When a 3-phase synchronous generator is supplying a zero power factor lagging load, the armature field affects the main field in the following way
72. Stability of a synchronous machine
73. The power factor of a synchronous motor is better than that of induction motor because
74. If in a synchronous motor, driving a given mechanical load and drawing current at a leading power factor from constant voltage supply its field excitation is increased, its power factor
75. A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because
76. If one-phase of a 3-phase synchronous motor is short-circuited, motor
77. If the field circuit of an unloaded salientpole synchronous motor gets suddenly open-circuited, then
78. In which of the following motors the stator and rotor fields rotate simultaneously ?
79. The speed of a synchronous motor
80. A rotory converter can also be run as a
81. The maximum speed variation in a 3-phase synchronous motor is
82. Which of the following resistances can be measured by conducting insulation resistance test on a synchronous motor ?
83. Due to which of the following reasons a synchronous motor fails to pull into synchronism after applying D.C. field current ?
84. In a synchronous motor, the maximum power developed depends on all of the following except
85. In a 3-phase synchronous motor, the negative phase sequence exists when the motor is
86. In a synchronous motor, damper windings are provided on
87. The induced e.m.f. in a synchronous motor working on leading power factor will be
88. The effect of increasing the load on a synchronous motor running with normal excitation is to
89. The net armature voltage of a synchronous motor is equal to the
90. The ratio of starting torque to running torque in a synchronous motor is
91. In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on
92. A 3-phase synchronous motor is running clockwise. If the direction of its field current is reversed
93. The magnitude of field flux in a 3-phase synchronous motor
94. The torque angle, in a synchronous motor, is the angle between
95. Hunting in a synchronous motor cannot be due to
96. By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ?
97. In a synchronous motor, V-curves represent relation between
98. In a 3-phase, 4-pole, 50 Hz synchronous motor, the frequency, pole number and load torque all are halved. The motor speed will be
99. A synchronous motor connected to infinite bus-bars has at constant full load, 100% excitation and unity power factor. On changing the excitation only, the armature current will have
100. Which of the following motors is non-self starting ?
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