Synchronous Motor

What are the two main types of synchronous motors?

• Brushless DC motors and AC motors

• Universal motors and DC motors

• Induction motors and stepper motors

• Synchronous reluctance motors and permanent magnet synchronous motors

Explain the working principle of a synchronous motor.

• The working principle of a synchronous motor is based on magnetic locking between the stator and rotor fields.

• Synchronous motors operate by converting thermal energy into mechanical energy.

• The working principle of a synchronous motor involves the use of hydraulic pressure.

• Synchronous motors work based on friction between the stator and rotor fields.

What are the advantages of using a synchronous motor?

• Inconsistent speed operation, high efficiency, poor power factor correction

• Variable speed operation, low efficiency, poor power factor correction

• Constant speed operation, high efficiency, good power factor correction

• Intermittent speed operation, moderate efficiency, average power factor correction

Discuss the disadvantages of synchronous motors.

• Synchronous motors are more efficient than induction motors

• Synchronous motors require external excitation, are less efficient, more expensive, and complex compared to induction motors.

• Synchronous motors do not require external excitation

• Synchronous motors are less complex than induction motors

In which applications are synchronous motors commonly used?

• Industrial processes, compressors, synchronous clocks

• Residential lighting, electric vehicles, smartphones

• Wind turbines, solar panels, submarines

• Agricultural machinery, refrigerators, traffic lights

Name one type of synchronous motor that does not require any external excitation.

• Permanent magnet synchronous motor

• Stepper motor

• Brushless DC motor

• Induction motor

How does a synchronous motor maintain a constant speed under varying loads?

• By using a variable frequency drive to adjust the speed based on load

• By changing the number of poles in the motor

• By increasing the resistance in the stator windings

• By adjusting the field current supplied to the rotor to keep the magnetic field in sync with the stator's field.

What is the role of the rotor in a synchronous motor?

• Controls the speed of the motor

• Regulates the voltage output

• Provides cooling for the motor

• Generates a rotating magnetic field

Why are synchronous motors preferred for high-power industrial applications?

• They operate at a constant speed regardless of the load, have high efficiency, and provide better power factor correction.

• They have lower efficiency compared to asynchronous motors

• They require more maintenance than asynchronous motors

• They are less expensive than asynchronous motors

What is the power factor of a synchronous motor at full load?

• 1.0 lagging

• 0.9 lagging

• 0.5 leading

• 0.8 leading