Stationary Engineer Electric UPDATED
ACTUAL Exam Questions and CORRECT
Answers
An AC circuit consists only of a pure inductance and a power source. The relationship between
the voltage and the current in this circuit is that the - CORRECT ANSWER - current lags
the voltage
The power factor of a load is equal to the ____________ power divided by the ____________
power. - CORRECT ANSWER - True ; apparent
A 10-ohms and 20-ohms resistor are connected in parallel. The total line current drawn by this
parallel combination is 30 amps. Under these conditions, the line voltage will be ____________
volts. - CORRECT ANSWER - 200
A 20-ohm resistor is connected in series with a parallel combination of two resistors, one of
which is 10-ohms, the other 40-ohms. If the voltage across the parallel combination is 40 volts,
the voltage across the 20-ohm series resistor is ________ volts. - CORRECT ANSWER -
100
A certain 120-volts single-phase AC circuit has a power factor of 80 percent and a watt-meter
reading of 1150 watts. The current drawn by the circuit is _________ amperes. - CORRECT
ANSWER - 12
If the voltage between lines of a 3-phase, 3-wire delta connected system is 2400 volts, then the
phase voltage is _____________ volts - CORRECT ANSWER - 2400
A circuit consists of an inductive reactance of 15 ohms and a resistor of 20 ohms in series across
a 100-volts, 60 cycles AC supply. The current in this circuit is ____________ amperes. -
CORRECT ANSWER -4
,A 3 phase, 3 wire, 208 volt, 60 cycles AC service supplies a balanced load consisting of three 30
ohms resistors connected wye. The line current under these conditions os MOST NEARLY
___________ amperes. - CORRECT ANSWER - 6.9
If the level of the electrolyte in a lead acid storage battery falls below the top of the plates
because of evaporations under normal operating conditions, it is BEST to add - CORRECT
ANSWER - Water
A 600 volt cartridge fuse must have knife blade contacts if its current rating exceeds
_____________ amperes. - CORRECT ANSWER - 60
When the magnitude of the short circuit currents in a feeder circuit must be limited, this is
USUALLY accomplished by means of - CORRECT ANSWER - reactors
The cross sectional area in circular mils of a standard cable having 37 strands, each of which ha a
diameter of 90 nils, is MOST NEARLY - CORRECT ANSWER - 300,000
A coil having an average diameter of 4 inches is to be made up from a 1,260 ft long length of
wire. The numbers of turns in this coil will be MOST NEARLY - CORRECT ANSWER -
1,200
The device commonly known as a growler is FREQUENTLY used to - CORRECT
ANSWER - test DC armature windings for shorts
When a megger is applied alternately to the two leads of a direct current electrolytic capacitor,
the reading will - CORRECT ANSWER - start at zero but increase gradually for one of the
connections
The device used to convert direct current to alternating current is called - CORRECT
ANSWER - inverters
,Of the following conditions, the one which is MOST likely to cause flashing or excessive arcing
from brush to brush in a motor is - CORRECT ANSWER - Excessively high voltage on
the line
The currents in the armature equalizer connections in a DC generator are - CORRECT
ANSWER - alternating currents
A generating station has one 1000 Kw and two 2000 Kw generators. To supply 2000 Kw MOST
economically, the operating conditions should be - CORRECT ANSWER - one 2000 Kw
generator at full load
The terminal voltage of a DC shunt generator having an armature current of 100 amperes, an
armature resistance of 0.02 ohms, and a generated E.M.F of 222 volts is MOST NEARLY
______________ volts. - CORRECT ANSWER - 220
The number of poles in the field of an alternator generating voltage at a frequency of 60 cycles
per second while rotating at 1200 rpm is - CORRECT ANSWER -6
If the field of a shunt motor opens while running, the motor will - CORRECT ANSWER -
run away
To reverse the direction of rotation of a cumulative compound motor, and not have it run as a
differential compound motor, reverse the connections to the ____________ field. - CORRECT
ANSWER - shunt field and to the series
A main contributing factor to motor stator failure usually is - CORRECT ANSWER - dirt
The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy loss is
__________ watts. - CORRECT ANSWER - 8,000
, The full load current of a three-phase 5 hp motor operating at 200 volts, 60 cycles, and having an
efficiency of 80 percent and a power factor of 85 percent is MOST NEARLY ____________
amperes. - CORRECT ANSWER - 14.4
Of the following motors, the one that has the best speed regulation is the motor. - CORRECT
ANSWER - shunt
The full load speed of a 60-cycle 208 volt, 3 phase induction motor having 6 poles and operating
with a slip of 10% is MOST NEARLY___________ r.p.m - CORRECT ANSWER - 1080
Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) - CORRECT
ANSWER - can be used for power factor correction
If the field current of a synchronous motor is increased to a point which makes the synchronous
motor overexcited, the - CORRECT ANSWER - motor will take a leading current
When transformers are to be operated in parallel, it is NOT necessary that the transformer have
the same - CORRECT ANSWER - KVA rating
A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80% when it is
supplying - CORRECT ANSWER - 160 KW
If the current in the primary of a current transformer is 500 amperes and the transformer has a
ratio of 100 to 5, an ammeter connected to the secondary will read MOST
NEARLY___________ amperes. - CORRECT ANSWER - 25
Assume that a switchboard ammeter which is connected to a current transformer is damaged and
must be removed without interrupting the service. Of the following, an ESSENTIAL precaution
to be taken before disconnecting the ammeter is to - CORRECT ANSWER - short the
secondary of the transformer
ACTUAL Exam Questions and CORRECT
Answers
An AC circuit consists only of a pure inductance and a power source. The relationship between
the voltage and the current in this circuit is that the - CORRECT ANSWER - current lags
the voltage
The power factor of a load is equal to the ____________ power divided by the ____________
power. - CORRECT ANSWER - True ; apparent
A 10-ohms and 20-ohms resistor are connected in parallel. The total line current drawn by this
parallel combination is 30 amps. Under these conditions, the line voltage will be ____________
volts. - CORRECT ANSWER - 200
A 20-ohm resistor is connected in series with a parallel combination of two resistors, one of
which is 10-ohms, the other 40-ohms. If the voltage across the parallel combination is 40 volts,
the voltage across the 20-ohm series resistor is ________ volts. - CORRECT ANSWER -
100
A certain 120-volts single-phase AC circuit has a power factor of 80 percent and a watt-meter
reading of 1150 watts. The current drawn by the circuit is _________ amperes. - CORRECT
ANSWER - 12
If the voltage between lines of a 3-phase, 3-wire delta connected system is 2400 volts, then the
phase voltage is _____________ volts - CORRECT ANSWER - 2400
A circuit consists of an inductive reactance of 15 ohms and a resistor of 20 ohms in series across
a 100-volts, 60 cycles AC supply. The current in this circuit is ____________ amperes. -
CORRECT ANSWER -4
,A 3 phase, 3 wire, 208 volt, 60 cycles AC service supplies a balanced load consisting of three 30
ohms resistors connected wye. The line current under these conditions os MOST NEARLY
___________ amperes. - CORRECT ANSWER - 6.9
If the level of the electrolyte in a lead acid storage battery falls below the top of the plates
because of evaporations under normal operating conditions, it is BEST to add - CORRECT
ANSWER - Water
A 600 volt cartridge fuse must have knife blade contacts if its current rating exceeds
_____________ amperes. - CORRECT ANSWER - 60
When the magnitude of the short circuit currents in a feeder circuit must be limited, this is
USUALLY accomplished by means of - CORRECT ANSWER - reactors
The cross sectional area in circular mils of a standard cable having 37 strands, each of which ha a
diameter of 90 nils, is MOST NEARLY - CORRECT ANSWER - 300,000
A coil having an average diameter of 4 inches is to be made up from a 1,260 ft long length of
wire. The numbers of turns in this coil will be MOST NEARLY - CORRECT ANSWER -
1,200
The device commonly known as a growler is FREQUENTLY used to - CORRECT
ANSWER - test DC armature windings for shorts
When a megger is applied alternately to the two leads of a direct current electrolytic capacitor,
the reading will - CORRECT ANSWER - start at zero but increase gradually for one of the
connections
The device used to convert direct current to alternating current is called - CORRECT
ANSWER - inverters
,Of the following conditions, the one which is MOST likely to cause flashing or excessive arcing
from brush to brush in a motor is - CORRECT ANSWER - Excessively high voltage on
the line
The currents in the armature equalizer connections in a DC generator are - CORRECT
ANSWER - alternating currents
A generating station has one 1000 Kw and two 2000 Kw generators. To supply 2000 Kw MOST
economically, the operating conditions should be - CORRECT ANSWER - one 2000 Kw
generator at full load
The terminal voltage of a DC shunt generator having an armature current of 100 amperes, an
armature resistance of 0.02 ohms, and a generated E.M.F of 222 volts is MOST NEARLY
______________ volts. - CORRECT ANSWER - 220
The number of poles in the field of an alternator generating voltage at a frequency of 60 cycles
per second while rotating at 1200 rpm is - CORRECT ANSWER -6
If the field of a shunt motor opens while running, the motor will - CORRECT ANSWER -
run away
To reverse the direction of rotation of a cumulative compound motor, and not have it run as a
differential compound motor, reverse the connections to the ____________ field. - CORRECT
ANSWER - shunt field and to the series
A main contributing factor to motor stator failure usually is - CORRECT ANSWER - dirt
The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy loss is
__________ watts. - CORRECT ANSWER - 8,000
, The full load current of a three-phase 5 hp motor operating at 200 volts, 60 cycles, and having an
efficiency of 80 percent and a power factor of 85 percent is MOST NEARLY ____________
amperes. - CORRECT ANSWER - 14.4
Of the following motors, the one that has the best speed regulation is the motor. - CORRECT
ANSWER - shunt
The full load speed of a 60-cycle 208 volt, 3 phase induction motor having 6 poles and operating
with a slip of 10% is MOST NEARLY___________ r.p.m - CORRECT ANSWER - 1080
Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) - CORRECT
ANSWER - can be used for power factor correction
If the field current of a synchronous motor is increased to a point which makes the synchronous
motor overexcited, the - CORRECT ANSWER - motor will take a leading current
When transformers are to be operated in parallel, it is NOT necessary that the transformer have
the same - CORRECT ANSWER - KVA rating
A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80% when it is
supplying - CORRECT ANSWER - 160 KW
If the current in the primary of a current transformer is 500 amperes and the transformer has a
ratio of 100 to 5, an ammeter connected to the secondary will read MOST
NEARLY___________ amperes. - CORRECT ANSWER - 25
Assume that a switchboard ammeter which is connected to a current transformer is damaged and
must be removed without interrupting the service. Of the following, an ESSENTIAL precaution
to be taken before disconnecting the ammeter is to - CORRECT ANSWER - short the
secondary of the transformer
