WorksheetsElectrical Machines Quiz
Total questions: 10
Worksheet time: 5mins
Which of the following is the most essential part of any rotating electrical machine?
Stator
Rotor
Air gap
Magnetic circuit
The direction of rotation of a DC motor can be reversed by reversing:
Only field current
Only armature current
Either field or armature current
Both field and armature current
In a transformer, the core is laminated mainly to reduce:
Copper losses
Eddy current losses
Hysteresis losses
Stray losses
The emf induced in the armature of a DC generator depends on:
Flux per pole
Speed of rotation
Number of armature conductors
All of the above
Which DC motor is most suitable for traction applications (electric trains, cranes)?
DC shunt motor
DC series motor
DC compound motor (cumulative)
DC separately excited motor
In a single-phase induction motor, the starting torque is produced with the help of:
Only main winding
Auxiliary winding + capacitor / shading rings / resistance
Only rotor bars
External DC supply
The efficiency of a transformer is maximum when:
Copper loss = Iron loss
Copper loss > Iron loss
Copper loss < Iron loss
Copper loss = Iron loss
The speed of a synchronous motor is:
Always less than synchronous speed
Always greater than synchronous speed
Equal to synchronous speed
Depends on load
In a 3-phase induction motor, slip is:
Zero at no-load
Maximum at standstill
Always negative during motoring
Always 100% at full load
Which of the following machines can operate both as motor and generator without any change in construction?
DC series motor
Synchronous machine
Single-phase induction motor
Shaded pole motor
