Question 1

The synchronous motor has the same type of stator windings as other ____.&#10;A) brushless DC motors&#10;B) high torque motors&#10;C) stepper motors&#10;D) three-phase motors

Accepted Answer

The synchronous motor has the same type of stator windings as three-phase motors.

Question 2

The power factor of the synchronous motor can be changed by adjusting the DC excitation current to the rotor.

Accepted Answer

By adjusting the DC excitation current to the rotor, the power factor of a synchronous motor can be increased or decreased. This is because the DC excitation current controls the magnitude and phase angle of the rotor magnetic field, which in turn influences the amount of reactive power taken by the motor from the power system.

Question 3

When a synchronous motor is operated at no load and used for power factor correction, it is generally referred to as a ____.&#10;A) reflux condenser&#10;B) discharge resistor&#10;C) synchronous condenser&#10;D) synchronous corrector

Accepted Answer

When a synchronous motor is operated at no load and used only for power factor correction, it is commonly referred to as a synchronous condenser. Its purpose is to generate reactive power, which helps to improve the power factor of the system. Reflux condensers and discharge resistors are not related to power factor correction, and there is no such thing as a "synchronous corrector."

Question 4

The brushless exciter is constructed by incorporating a small three-phase alternator winding on the ____ of the motor.&#10;A) shaft&#10;B) casing&#10;C) stator&#10;D) rotator

Accepted Answer

The brushless exciter is constructed by incorporating a small three-phase alternator winding on the shaft of the motor. This allows for the excitation of the main field without the use of brushes or slip rings, which improves reliability and reduces maintenance requirements.

Question 5

The synchronous motor will run at a variable speed from no load to full load.

Accepted Answer

The synchronous motor runs at a constant speed, which is determined by the frequency of the power supply and the number of poles in the motor. It does not vary with load.

Question 6

The rotor of a synchronous motor contains a set of type &#34;A&#34; squirrel-cage bars.

Accepted Answer

The answer of The rotor of a synchronous motor contains...

Question 7

In coils designed for AC current, the resistance of the wire is used to limit the flow of current.

Accepted Answer

In coils designed for AC current, the inductance of the coil is used to limit the flow of current. The resistance of the wire is still present, but its effect is secondary to the inductance.

Question 8

As load is added to the synchronous motor , the magnetic field of the rotor remains locked with the rotating magnetic field and the rotor turns at ____ speed.&#10;A) the same&#10;B) a lower&#10;C) a higher&#10;D) the maximum

Accepted Answer

In a synchronous motor, the rotor rotates at the same speed as the rotating magnetic field generated by the stator. As load is added, the magnetic field of the rotor remains locked with the rotating magnetic field of the stator, and therefore, the rotor continues to turn at the same speed.

Question 9

The winding of a synchronous motor is ____.&#10;A) one continuous set of coils&#10;B) two continuous sets of coils&#10;C) three different sets of coils&#10;D) four different sets of coils

Accepted Answer

The winding of a synchronous motor is one continuous set of coils.

Question 10

Many large synchronous motors use a brushless exciter instead of slip rings and brushes.

Accepted Answer

Large synchronous motors often use brushless exciters to avoid the maintenance issues associated with slip rings and brushes.

Deck 17: The Synchronous Motor