Alternator and Induction Generator MCQs (Part-12)

What is the primary function of the rotor in an alternator?

A To induce voltage in the stator windings
B To provide mechanical support to the stator
C To generate a rotating magnetic field
D To regulate the output frequency

Why are cylindrical rotors preferred in high-speed alternators?

A They reduce stator losses
B They minimize wind resistance and maintain mechanical balance
C They increase reactive power
D They increase the load capacity

What determines the synchronous speed of an alternator?

A Rotor resistance
B Frequency and number of poles
C Excitation voltage
D Load on the alternator

What is the main purpose of voltage regulation in alternators?

A To adjust the rotor speed
B To maintain constant output voltage under varying loads
C To improve the frequency of the output
D To reduce power factor losses

How does increasing the excitation current affect an alternator’s output?

A It decreases the frequency
B It increases the output voltage
C It reduces the efficiency
D It improves the cooling system

What is the main purpose of parallel operation of alternators?

A It eliminates the need for load sharing
B It allows flexibility and reliability in power systems
C It reduces harmonics in the system
D It improves rotor cooling efficiency

What is slip in an induction generator?

A The difference between rotor and stator voltage
B The difference between synchronous speed and rotor speed
C The relative speed of the stator field
D The percentage of reactive power in the system

How is self-excitation achieved in induction generators?

A By connecting an external DC source to the rotor
B By using capacitors to supply reactive power
C By increasing rotor resistance
D By maintaining synchronous speed

What is the role of a voltage regulator in an alternator?

A To control the rotor speed
B To adjust the excitation current and maintain constant voltage
C To synchronize the alternator with the grid
D To monitor the power factor

Why are harmonics undesirable in alternators?

A They improve system efficiency
B They cause overheating and reduce power quality
C They stabilize the rotor speed
D They increase output voltage

What is the environmental benefit of using DFIGs in wind power systems?

A They generate DC power directly
B They reduce greenhouse gas emissions by enabling clean energy generation
C They operate at fixed speeds
D They do not require reactive power compensation

What is the purpose of reactive power compensation in power systems?

A To increase rotor efficiency
B To maintain voltage stability and improve power factor
C To reduce stator losses
D To eliminate load sharing

What is the primary environmental benefit of using induction generators in renewable energy systems?

A Reduced greenhouse gas emissions
B Reduced dependence on fossil fuels
C Increased electrical losses
D Increased harmonic distortion

What is the main benefit of hybrid energy systems in power generation?

A They operate only on renewable sources
B They combine renewable and non-renewable sources for reliability
C They reduce system efficiency
D They eliminate the need for grid synchronization

Why is periodic maintenance necessary for alternators?

A To increase the power factor
B To ensure reliable operation and prevent faults
C To stabilize system frequency
D To prevent harmonic distortions

What is the environmental impact of using alternators in renewable energy systems?

A Increased greenhouse gas emissions
B Reduced carbon footprint due to clean energy integration
C Higher noise pollution
D Increased system efficiency

How do hybrid systems improve power reliability?

A By eliminating reactive power
B By integrating renewable and non-renewable energy sources
C By operating at a fixed frequency
D By reducing the alternator’s efficiency

What is the function of a differential protection relay in an alternator?

A To detect internal faults like short circuits in stator windings
B To regulate voltage fluctuations
C To eliminate harmonic distortions
D To synchronize the alternator with the grid

How is power factor controlled in alternators?

A By adjusting the rotor speed
B By controlling the excitation current to regulate reactive power
C By increasing stator voltage
D By reducing the load

Why are harmonic distortions a concern in alternators?

A They improve energy generation
B They reduce power quality and cause overheating
C They stabilize system voltage
D They increase system reliability