NEW
Font size
WorksheetsMCQs on Synchronous Motor
Total questions: 12
Worksheet time: 6mins
What is the principle of operation of a synchronous motor?
Electromagnetic induction
Interaction between a rotating magnetic field and a stationary magnetic field
Lenz's law
Faraday's law of electromagnetic induction
What is the synchronous speed of a 4-pole, 50 Hz synchronous motor?
1000 rpm
1500 rpm
3000 rpm
750 rpm
What is the power factor of a synchronous motor?
Always lagging
Always leading
Can be leading, lagging, or unity
Always unity
What is the purpose of damper windings in a synchronous motor?
To improve the power factor
To provide starting torque
To stabilize the rotor
To reduce losses
How is a synchronous motor started?
By directly connecting it to the supply
By using a starter motor
By using a pony motor
By using damper windings and external excitation
What is the effect of increasing the field excitation of a synchronous motor?
Increases the power factor
Decreases the power factor
Has no effect on the power factor
Increases the speed
What is the V-curve of a synchronous motor?
A plot of armature current vs. field current at constant load
A plot of power factor vs. field current at constant load
A plot of speed vs. field current at constant load
A plot of torque vs. field current at constant load
What is the effect of increasing the load on a synchronous motor?
The rotor speed increases
The rotor speed decreases
The rotor speed remains constant
The rotor speed fluctuates
What is the maximum power output of a synchronous motor?
When the load angle is 0 degrees
When the load angle is 90 degrees
When the load angle is 180 degrees
When the load angle is 45 degrees
What is the synchronous condenser?
A synchronous motor running at no load
A synchronous generator running at no load
A device to improve the power factor
A device to regulate the voltage
In which applications are synchronous motors commonly used?
Low-speed drives
High-speed drives
Constant speed drives
Variable speed drives
What is the main advantage of a synchronous motor over an induction motor?
Higher efficiency
Lower cost
Higher power factor
Simpler construction
