What is the main advantage of operating synchronous motors in parallel?
A Increased torque
B Load sharing
C Increased power factor
D Reduced slip
When synchronous motors are operated in parallel, they can share the load equally, balancing the power supply requirements. This ensures stable operation and allows for better efficiency and redundancy in industrial applications.
What is the effect of paralleling induction motors with different ratings?
A Better torque performance
B Uneven load sharing
C Improved power factor
D Increased efficiency
Paralleling induction motors with different ratings can cause uneven load sharing because the motors with higher ratings will tend to carry more load, leading to inefficient operation and possible overload on smaller motors.
What is the purpose of synchronizing a synchronous motor before connecting it to the grid?
A Match speed and phase
B Decrease current
C Adjust excitation
D Control voltage
Before connecting a synchronous motor to the grid, it must be synchronized, meaning the motor’s speed and phase must match that of the grid’s supply. This prevents system instability and ensures efficient operation.
What is the primary factor that determines the load sharing between synchronous motors in parallel?
A Current draw
B Rotor speed
C Voltage regulation
D Excitation level
The excitation level of synchronous motors determines their ability to share the load in parallel operation. Motors with higher excitation tend to supply more power, while motors with lower excitation supply less.
What happens when the load on a synchronous motor exceeds its rated capacity?
A The motor loses synchronism
B The motor increases torque
C The motor continues to operate normally
D The motor speeds up
If the load on a synchronous motor exceeds its rated capacity, the motor cannot maintain synchronization with the stator’s magnetic field. This results in the motor falling out of synchronism and losing stable operation.
In a parallel operation of synchronous motors, what must be the same for each motor?
A Voltage and frequency
B Current and excitation
C Rotor resistance
D Torque and speed
For synchronous motors to operate in parallel, they must have the same voltage and frequency. This ensures they run at the same speed and can share the load efficiently without causing instability or damage.
What causes an imbalance in load sharing between two synchronous motors operating in parallel?
A Different excitation levels
B Different power factors
C Different rotor speeds
D Different torque speeds
An imbalance in load sharing can occur if the excitation levels of the synchronous motors are not equal. Motors with higher excitation will absorb more load, while those with lower excitation will carry less, leading to inefficient load distribution.
When operating synchronous motors in parallel, what is the effect of varying load on the motors?
A Increased slip
B Decreased voltage
C Uneven load distribution
D Improved efficiency
When synchronous motors operate in parallel, varying loads can cause uneven distribution. Motors with higher excitation will take a larger share of the load, while motors with lower excitation will contribute less, potentially overloading one motor.
What is the function of the automatic synchronizer in parallel operation of synchronous generators?
A Control power factor
B Match phase and frequency
C Regulate speed
D Adjust voltage
The automatic synchronizer ensures that synchronous generators are synchronized correctly before they are connected in parallel. It matches the frequency, phase, and voltage of the generator to the grid, ensuring stable operation.
What can cause a synchronous motor to lose synchronism when operating in parallel?
A Reduced voltage
B Excessive excitation
C Overloading
D Insufficient load
When a synchronous motor is overloaded, it cannot maintain its synchronism with the grid’s magnetic field. This leads to the motor falling out of synchronism, which can cause instability and potentially damage the system.
How does paralleling induction motors help in industrial applications?
A It increases power factor
B It reduces energy consumption
C It reduces speed
D It improves system stability
Paralleling induction motors helps improve system stability by providing redundancy. If one motor fails or is underperforming, the other motors in parallel can take on the load, ensuring uninterrupted operation and preventing downtime.
What is the impact of a motor’s power factor on the load sharing in parallel operation?
A It causes synchronization failure
B Higher power factor improves load sharing
C It has no impact
D Lower power factor improves load sharing
A higher power factor in synchronous motors allows them to operate more efficiently and share the load better. It reduces losses and ensures that each motor in parallel contributes optimally to the system.
What is the purpose of a load sharing controller in a parallel operation of synchronous generators?
A To balance the load
B To control rotor speed
C To adjust excitation
D To synchronize frequency
A load sharing controller automatically adjusts the load distribution between synchronous generators operating in parallel. It ensures that each generator shares the load proportionally, improving overall system efficiency and preventing overloads.
What happens if synchronous generators with different ratings are connected in parallel?
A Better synchronization
B Increased voltage stability
C Uneven power sharing
D Reduced power factor
When synchronous generators with different ratings are connected in parallel, the larger generator tends to share more of the load, while the smaller generator takes on less. This can lead to uneven load sharing and potential instability.
What happens when a synchronous motor operates with excessive excitation in parallel with others?
A It draws less current
B It operates at a lower speed
C It supplies more active power
D It supplies more reactive power
A synchronous motor with excessive excitation will generate more reactive power, leading to it supplying a larger portion of the load’s reactive power. This can affect load sharing and reduce overall system efficiency if not properly balanced.