Electrical Machines Questions and Answers – Synchronous Machine Stability

This set of Electrical Machines Multiple Choice Questions & Answers (MCQs) focuses on “Synchronous Machine Stability”.

1. Steady state stability limit is defined as maximum power flow possible through a particular point without loss of stability when the ___________
a) power is increased gradually
b) power is increased suddenly
c) power is reduced gradually
d) power is reduces suddenly
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2. If the load angle is increased till 135°, the consequence will be ___________
a) loss of synchronism
b) no alternation of synchronism
c) increase in stability limit
d) reduction in stability limit
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3. The steady state limit can be improved by ___________

i. Increasing excitation
ii. reducing reactance
iii. using series capacitors

a) i, ii, iii
b) i, ii
c) iii only
d) ii, iii
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4. Series capacitors will improve the ___________
a) SSSL
b) Transient stability
c) Hunting
d) Stiffness
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5. Transient stability limit is less important than SSSL.
a) True
b) False
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6. (i) Transient stability is lower than SSSL.
(ii) Transient disturbances are more common.
a) i and ii both are true
b) i false, ii true
c) i true, ii false
d) Both are false
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7. The supply voltage to an induction motor is decreased by 10%. By what percentage, approximately, will the maximum torque decrease?
a) 5%
b) 10%
c) 20%
d) 40%
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8. In a salient pole synchronous machine the air gap is least under the middle of the pole shoe and increases outwards.
a) True
b) False
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9. If it is planned to bring an incoming alternator to the operating alternator in parallel, then which of the criteria can be ignored?
a) Prime mover speed
b) Voltage magnitude
c) Frequency
d) Phase sequence of the alternator
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10. Which one of the following is the base reason to place field on rotor in the alternator?
a) Small power in field circuit
b) Insulation of high voltage is made easy on stator than on rotor
c) Huge power in stator
d) Large current in the stator
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Sanfoundry Global Education & Learning Series – Electrical Machines.

To practice all areas of Electrical Machines, here is complete set of 1000+ Multiple Choice Questions and Answers.