IEC Year 3 Semester 2 Questions And Answers 100% Guaranteed Success.
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IEC
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IEC
IEC Year 3 Semester 2 Questions And Answers 100% Guaranteed Success.
A shunt DC motor is a type of DC motor. - correct answer. A.
True
If a motor has field leads that are marked F1 and F2, this is a ___ motor. - correct answer. A.
DC motor
A 10°C increase in the operating te...
IEC Year 3 Semester 2 Questions And
Answers 100% Guaranteed Success.
A shunt DC motor is a type of DC motor. - correct answer. A.
True
If a motor has field leads that are marked F1 and F2, this is a ___ motor. - correct
answer. A.
DC motor
A 10°C increase in the operating temperature can decrease the life expectancy of a DC
motor by as much as ___. - correct answer. C.
1/2
Which of the following are types of 1-ph AC motors? - correct answer. E.
all of these
A ___ motor can be operated from a single-phase AC circuit. - correct answer. E.
all of these
Single-phase AC motors are readily available in hp ratings of 1/6 to ___. - correct
answer. E.
10
AC motors can be rated in horsepower or kilowatts. - correct answer. A.
True
___ provides standards for the construction of motors and other electrical equipment. -
correct answer. C.
both a and b
NEMA Design C motors are characterized by ___ starting torque. - correct answer. B.
high
NEMA Design C motors are characterized by ___ starting current. - correct answer. C.
low
,A single-phase AC motor consists of a start winding and a run winding. - correct
answer. A.
True
The ___ is the part of a 3Ø motor that doesn't rotate. - correct answer. B.
stator
When a 230/460-volt dual-voltage 3Ø motor is properly connected to a 480-volt circuit,
the current through each winding is ___. - correct answer. B.
the same as it would be for a 240-volt circuit
___ is the turning force exerted on the armature in a motor. - correct answer. C.
Torque
A(n) ___ is a device that changes the direction of current flow through the armature
loop. - correct answer. D.
Commutator
A commutator is a device that changes the direction of current flow through the
armature loop in a(n) ___ motor(s). - correct answer. B.
DC
A commutator is a device that changes the direction of current flow through the
armature loop in a(n) ___ motor(s). - correct answer. B.
DC
The circuit conductors of a DC motor are connected directly to the ___. - correct
answer. A.
brushes
The brushes in a DC motor are made of ___. - correct answer. C.
carbon
___ is (are) a type (types) of DC motor(s). - correct answer. E.
All of these
The industry standard used to reverse a DC motor is to reverse the ___ leads. - correct
answer. B.
armature
A ___ motor can operate on either AC or DC power. - correct answer. A.
universal
DC motors manufactured in the United States are generally rated in ___. - correct
answer. A.
,HP
What is the efficiency of a 10 hp DC motor that draws 31 amps at 300 volts? - correct
answer. D.
80%
Refer to the motor nameplate shown in Figure 230.110. When the motor is connected to
a 230-volt circuit, the motor branch circuit current is ___ what it would be for a 115-volt
circuit. - correct answer. B.
half
Refer to the motor nameplate shown in Figure 230.110. If the supply circuit is 120 volts,
you would connect as shown at ___ where the motor leads are connected to the T-
strips. - correct answer. A.
For an AC motor, the motor leads in the terminal box originate at the ___. - correct
answer. B.
stator
The part of an AC motor that rotates is the ___. - correct answer. A.
rotor
An AC motor operates by changing the direction of current through the ___. - correct
answer. D.
stator
The speed of a single-phase AC motor can be easily controlled by changing the ___.
I. frequency II. number of poles III. voltage - correct answer. E.
I or II only
___ torque is the torque required to produce the nameplate-rated output power
(horsepower) and speed (RPMs) when driving a load. - correct answer. D.
Full-load
Large horsepower single-phase AC motors are generally not used where the conditions
permit the use of three-phase motors because 1-ph motors ___.
I. are less efficient
II. require larger circuit conductors - correct answer. C.
both I & II
To reverse the direction of rotation for a single-phase motor, the ___ connections to line
1 and line 2, respectively, are reversed. - correct answer. D.
T5 & T8
Which 1Ø capacitor motor connection diagram, shown above in Figure 228.201, is
correct where clockwise rotation is desired? - correct answer. B.
, II & IV only
___ is a basic type of 3-phase motor.
I. Squirrel-cage induction II. Wound-rotor III. Synchronous - correct answer. E.
I, II & III
A ___ motor utilizes a bank of variable resistors that are external to the motor. - correct
answer. B.
wound-rotor
A ___ motor rotates at a constant speed, regardless of how heavily loaded. - correct
answer. C.
synchronous
The most commonly used 3-phase motor is the ____ motor. - correct answer. A.
squirrel-cage induction
Three separate winding sets are contained in the stator of a 3-phase motor. These are
set at ___ degrees apart. - correct answer. D.
120
The rotating magnetic fields in a 3Ø motor are ___ electrical degrees apart. - correct
answer. C.
120
A rotating magnetic field rotates in the ___ of a 3-phase AC motor. - correct answer.
B.
stator
If a 3-phase motor is connected to power but is not rotating in the desired direction, the
rotation can be changed by swapping any two "hot" circuit conductors ___. - correct
answer. D.
any of these
To ensure that shaft rotation is correct and motor-driven equipment is ready to be
energized for the first time, ___. - correct answer. C.
start-up protocols must be followed
Prior to disconnecting a 3-phase service drop or lateral, the phase rotation at the
service equipment terminals should be checked with a meter and noted. When the
service equipment is reconnected, the connection should be made so that the rotation
present at the terminals is ___. - correct answer. B.
the same as the noted phase rotation
Nine-lead 3Ø motors are usually internally (factory) connected as either a ___
configuration. - correct answer. B.
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