Worksheetsrecap the previous session. 3
Total questions: 14
Worksheet time: 7mins
An electric generator is a machine that uses ________ to convert mechanical energy into electric energy.
magnetism
watts
amps
volts
The device that provides the mechanical energy input to a generator is called the
prime mover
rotor
stator
armature
An electric motor uses _________ to operate.
electric current
heat
magnetism
electric current and magnetism
Generators operate on the principle that a voltage is induced in a conductor whenever the conductor is _______ a magnetic field so as to cut lines of force.
placed in
seen in
moved through
conducted in
Torque is best defined as:
the change in motor speed due to armature reaction
the turning force produced by a motor
the difference between the no-load and full-load speed of a motor
the opposing force produced in a motor’s armature.
Which of the following is not a requirement for motor action?
An external source of voltage
A magnetic field
A source of mechanical energy
A conductor
The purpose of a commutator on a DC motor is
to change AC to DC.
to adjust the speed of the motor.
to maintain the proper direction of current flow in the armature conductors.
to adjust the torque of the motor.
The two basic categories of motors are
low and high torque
AC and DC
less and more than 1 HP
low and high speed
One advantage DC type motors have over AC types is that
they use a more common type of voltage source
their speed can be easily varied
they require less maintenance
they are less expensive to manufacture
Which of the following is not a rotary part in the DC motor
Rotor.
Slip rings.
Commutator.
Field Winding.
In DC motors Torque depends on -----?
Voltage.
Speed
Armature current
Back e.m.f.
Which of the following motors is used where an extensive range of control is required?
Induction Motor
Synchronous Motor
DC Motors
AC Motor
If the DC motor voltage supply is increased then….will be decreased?
Operating speed
Starting torque
Full load current
Efficiency
Flemming's left-hand rules determine…?
Mechanical strength
Motor stability
The direction of Motor’s rotation
Motor working
