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WorksheetsCh4 Quiz 460
Total questions: 20
Worksheet time: 10mins
An electrical machine is a device that
Converts electrical energy into heat only
Converts mechanical energy into electrical energy only
Operates with electrical energy as input or output
Stores electrical energy
Which of the following is NOT a type of electrical machine?
DC machine
AC machine
Transformer
Rectifier
A DC generator mainly converts
Electrical power to mechanical power
Mechanical power to electrical power
Electrical power to heat
Magnetic energy to electrical energy
The voltage generated in a DC generator is originally
Pure DC
Pulsating DC
AC before rectification
Constant DC
In an AC generator, slip rings are used to
Convert AC to DC
Maintain constant polarity
Connect rotating coil to external circuit
Increase magnetic flux
DC output is obtained in a DC generator by using
Slip rings
Brushes only
Commutator
Laminated core
A commutator acts as
Electrical amplifier
Mechanical rectifier
Voltage regulator
Magnetic core
Which part of a DC machine carries the armature winding?
Stator
Shaft
Rotor
Pole shoe
The magnetic field in a DC machine is produced by
Armature winding
Field winding
Commutator
Brushes
Wave winding in a DC machine is suitable for
High current, low voltage
Low current, high voltage
High current, high voltage
Low current, low voltage
For a lap winding DC machine with p poles, the number of parallel paths is
2
p
2p
1
In a DC motor, the induced emf is known as
Generated emf
Terminal emf
Back emf
Supply emf
Counter emf in a DC motor
Assists the supply voltage
Acts against the supply voltage
Is zero during operation
Increases current
A separately excited DC machine has
Field winding connected in series with armature
Field winding connected in parallel with armature
No connection between field and armature
Only one winding
Which self-excited DC motor has field winding connected in parallel with armature?
Series motor
Shunt motor
Compound motor
Separately excited motor
Slip in an induction motor is zero when the rotor
Is at standstill
Runs faster than synchronous speed
Runs at synchronous speed
Is overloaded
DC machines are commonly used in applications requiring
Constant speed only
Low starting torque
Precise speed control
No speed variation
What is the primary function of the field winding in a DC motor?
To generate magnetic field
To rectify the output voltage
To convert electrical energy to mechanical energy
To provide mechanical support
Which of the following components is essential for the operation of a DC motor?
Transformer
Capacitor
Inductor
Commutator
Which type of winding is used in a DC machine to achieve high voltage?
Lap winding
Wave winding
Spiral winding
Coil winding
