3A2: Chapter 9,10,11 Practice
Questions and Already Passed
Answers 2026 Update.
what does MCC stand for - Answer motor control center
what is the name of the electrical device that is usually open but may be closed to connect one
side of a bus to the other? - Answer tie breaker
in reference to a circuit diagram of a high voltage power supply, what does ATS stand for? -
Answer automatic transfer switch
in a high voltage power supply, what is a duel fed system - Answer where two independent
power lines are used to supply the same load
in a dual supply system, what are the normal positions of both incoming feeder breakers? -
Answer normally closed (energized)
in dual supply system, what is the normal position of the main tie breaker - Answer normally
open
on an ac generator panel, what is the function of the exciter field current meter - Answer its
an ammeter that measure how much current is supplied to the field windings
on a ac generator panel, what is the function of the exciter field voltage meter - Answer its a
voltmeter that measures the voltage applied to the field windings
what unit does the ac generator frequency meter display - Answer hertz
what instrument on an ac generator panel displays the total accumulated power delivered by
the generator - Answer kilowatt hour meter
what instrument on a ac generator panel displays the reactive power being generated by the
generator - Answer KVAr meter
a _______ is the simplest form of over current protection for a electrical circuit - Answer fuse
,state two types of fuses - Answer cartridge and plug
plug fuses are used on circuits _____ V or less - Answer 125
the max continuous current carrying capacity of a plug fuse is _____A - Answer 30
cartridge fuses are used on electrical circuits up to _______V - Answer 600
the standard ratings of cartridge fuses are ______V and _______V - Answer 250, 600
in a cartridge fuse, why is the fuse body filled with insulating porous powder - Answer to
rapidly extinguish the arc thereby interrupting the flow of current
time delay fuses are available in both cartridge's and plug type. true or false - Answer true
what typical and common electrical load uses time delay fuses - Answer induction motors,
due to high starting currents
what are the two parts of a time delay fuse - Answer thermal cut out and fuse link
the thermal cut-out in a time delay fuse operates on overload currents up to about ________% -
Answer 500
in a time delay fuse, currents above 500% are interrupted by the ______ - Answer fuse link
high voltage fuses are used on electrical circuits greater than _______V - Answer 600
state two types of high voltage fuse - Answer expulsion fuse and liquid filled fuse
which type of high voltage fuse contains a coil spring - Answer liquid filled fuse
what is an electrical safety switch - Answer a device that isolates parts of an electric circuit or
for changing connections in a circuit or system
safety switches are available in _____V and ______V ratings - Answer 240,600
, what is the name of the electrical protective device that gives visual indication of a circuit and
can be reset in the event of a fault - Answer circuit breaker
circuit breakers may be operated by remote _______ - Answer control relays
what is the purpose of a loss of excitation relay - Answer the relay shall trip if here is a loss of
field excitation on the generator
when a synchronous generator loses excitation, what happens - Answer the rotor accelerates
and it operates as a induction generator running above synchronous speed. the generator then
draws inductive reactive power from the system instead of the supplying it. this is opposite to
what its supposed to do
what is the purpose of an over excitation relay - Answer when the ratio of voltage to
frequency is exceeded, it will trip. this prevents over excitation
when is a loss synchronism relay - Answer this relay trips when two areas of power systems
or two interconnected systems lose synchronism. this would cause large voltage and currents
throughout the system which can damage the generator and system
state a way in which unbalanced currents (negative phase sequence) could be caused in a
generator - Answer open phase, line to ground fault, phase to phase fault, improper air gap
between rotor and stator
a generator over voltage relay is typically set at ____% of the rated voltage - Answer 110
a generator under voltage relay is typically set at ______% of the rated voltage - Answer 90
in a turbine generator that is synchronized with another generator, what is an example of how a
reversal of power could occur - Answer the prime mover fails and the generator then
becomes a motor which draws current and the prime mover
what is an example of a "dead generator" - Answer the circuit breaker is closed on a
generator that is on its turning gear. it then behaves as a motor drawing very high starting
current
in general, over frequency in a generator doesn't pose any danger unless ______% is exceeded -
Answer 105
Questions and Already Passed
Answers 2026 Update.
what does MCC stand for - Answer motor control center
what is the name of the electrical device that is usually open but may be closed to connect one
side of a bus to the other? - Answer tie breaker
in reference to a circuit diagram of a high voltage power supply, what does ATS stand for? -
Answer automatic transfer switch
in a high voltage power supply, what is a duel fed system - Answer where two independent
power lines are used to supply the same load
in a dual supply system, what are the normal positions of both incoming feeder breakers? -
Answer normally closed (energized)
in dual supply system, what is the normal position of the main tie breaker - Answer normally
open
on an ac generator panel, what is the function of the exciter field current meter - Answer its
an ammeter that measure how much current is supplied to the field windings
on a ac generator panel, what is the function of the exciter field voltage meter - Answer its a
voltmeter that measures the voltage applied to the field windings
what unit does the ac generator frequency meter display - Answer hertz
what instrument on an ac generator panel displays the total accumulated power delivered by
the generator - Answer kilowatt hour meter
what instrument on a ac generator panel displays the reactive power being generated by the
generator - Answer KVAr meter
a _______ is the simplest form of over current protection for a electrical circuit - Answer fuse
,state two types of fuses - Answer cartridge and plug
plug fuses are used on circuits _____ V or less - Answer 125
the max continuous current carrying capacity of a plug fuse is _____A - Answer 30
cartridge fuses are used on electrical circuits up to _______V - Answer 600
the standard ratings of cartridge fuses are ______V and _______V - Answer 250, 600
in a cartridge fuse, why is the fuse body filled with insulating porous powder - Answer to
rapidly extinguish the arc thereby interrupting the flow of current
time delay fuses are available in both cartridge's and plug type. true or false - Answer true
what typical and common electrical load uses time delay fuses - Answer induction motors,
due to high starting currents
what are the two parts of a time delay fuse - Answer thermal cut out and fuse link
the thermal cut-out in a time delay fuse operates on overload currents up to about ________% -
Answer 500
in a time delay fuse, currents above 500% are interrupted by the ______ - Answer fuse link
high voltage fuses are used on electrical circuits greater than _______V - Answer 600
state two types of high voltage fuse - Answer expulsion fuse and liquid filled fuse
which type of high voltage fuse contains a coil spring - Answer liquid filled fuse
what is an electrical safety switch - Answer a device that isolates parts of an electric circuit or
for changing connections in a circuit or system
safety switches are available in _____V and ______V ratings - Answer 240,600
, what is the name of the electrical protective device that gives visual indication of a circuit and
can be reset in the event of a fault - Answer circuit breaker
circuit breakers may be operated by remote _______ - Answer control relays
what is the purpose of a loss of excitation relay - Answer the relay shall trip if here is a loss of
field excitation on the generator
when a synchronous generator loses excitation, what happens - Answer the rotor accelerates
and it operates as a induction generator running above synchronous speed. the generator then
draws inductive reactive power from the system instead of the supplying it. this is opposite to
what its supposed to do
what is the purpose of an over excitation relay - Answer when the ratio of voltage to
frequency is exceeded, it will trip. this prevents over excitation
when is a loss synchronism relay - Answer this relay trips when two areas of power systems
or two interconnected systems lose synchronism. this would cause large voltage and currents
throughout the system which can damage the generator and system
state a way in which unbalanced currents (negative phase sequence) could be caused in a
generator - Answer open phase, line to ground fault, phase to phase fault, improper air gap
between rotor and stator
a generator over voltage relay is typically set at ____% of the rated voltage - Answer 110
a generator under voltage relay is typically set at ______% of the rated voltage - Answer 90
in a turbine generator that is synchronized with another generator, what is an example of how a
reversal of power could occur - Answer the prime mover fails and the generator then
becomes a motor which draws current and the prime mover
what is an example of a "dead generator" - Answer the circuit breaker is closed on a
generator that is on its turning gear. it then behaves as a motor drawing very high starting
current
in general, over frequency in a generator doesn't pose any danger unless ______% is exceeded -
Answer 105
