Stationary Engineer Electric Exam Questions with All
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 - Answercurrent lags the
voltage
/.The power factor of a load is equal to the ____________ power divided by the
____________ power. - AnswerTrue ; 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. - Answer200
/.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.
- Answer100
/.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. - Answer12
/.If the voltage between lines of a 3-phase, 3-wire delta connected system is 2400 volts,
then the phase voltage is _____________ volts - Answer2400
/.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. - Answer4
/.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. - Answer6.9
/.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 -
AnswerWater
/.A 600 volt cartridge fuse must have knife blade contacts if its current rating exceeds
_____________ amperes. - Answer60
/.When the magnitude of the short circuit currents in a feeder circuit must be limited, this
is USUALLY accomplished by means of - Answerreactors
,/.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 - Answer300,000
/.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 - Answer1,200
/.The device commonly known as a growler is FREQUENTLY used to - Answertest DC
armature windings for shorts
/.When a megger is applied alternately to the two leads of a direct current electrolytic
capacitor, the reading will - Answerstart at zero but increase gradually for one of the
connections
/.The device used to convert direct current to alternating current is called -
Answerinverters
/.Of the following conditions, the one which is MOST likely to cause flashing or
excessive arcing from brush to brush in a motor is - AnswerExcessively high voltage on
the line
/.The currents in the armature equalizer connections in a DC generator are -
Answeralternating currents
/.A generating station has one 1000 Kw and two 2000 Kw generators. To supply 2000
Kw MOST economically, the operating conditions should be - Answerone 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. - Answer220
/.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 - Answer6
/.If the field of a shunt motor opens while running, the motor will - Answerrun 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. - Answershunt field and to the series
/.A main contributing factor to motor stator failure usually is - Answerdirt
/.The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy
loss is __________ watts. - Answer8,000
, /.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. - Answer14.4
/.Of the following motors, the one that has the best speed regulation is the motor. -
Answershunt
/.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 - Answer1080
/.Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) -
Answercan 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 - Answermotor will take a leading current
/.When transformers are to be operated in parallel, it is NOT necessary that the
transformer have the same - AnswerKVA rating
/.A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80%
when it is supplying - Answer160 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. - Answer25
/.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 -
Answershort the secondary of the transformer
/.A DC relay is rated at 6 volts and 120 ohms. This relay can be operated from a 120
volt line by connecting a ___________ ohm resistance in __________ with relay -
Answer2280: series
/.Some relays are provided with dash-pots. The FUNCTION of these dash-pots is to
provide - Answerdelayed time action
/.An ammeter has a full scale deflection for a current of 0.01 amperes and an internal
resistance of 20 ohms. In order to have the ammeter read full-scale for a current of 10
amperes and not damage its movement, a shunt should be used having a value
of__________ ohms. - Answer0.02
/.An air circuit breaker has contacts that flash. The MOST probable cause of this trouble
is that the - Answerbarriers are broken
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 - Answercurrent lags the
voltage
/.The power factor of a load is equal to the ____________ power divided by the
____________ power. - AnswerTrue ; 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. - Answer200
/.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.
- Answer100
/.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. - Answer12
/.If the voltage between lines of a 3-phase, 3-wire delta connected system is 2400 volts,
then the phase voltage is _____________ volts - Answer2400
/.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. - Answer4
/.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. - Answer6.9
/.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 -
AnswerWater
/.A 600 volt cartridge fuse must have knife blade contacts if its current rating exceeds
_____________ amperes. - Answer60
/.When the magnitude of the short circuit currents in a feeder circuit must be limited, this
is USUALLY accomplished by means of - Answerreactors
,/.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 - Answer300,000
/.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 - Answer1,200
/.The device commonly known as a growler is FREQUENTLY used to - Answertest DC
armature windings for shorts
/.When a megger is applied alternately to the two leads of a direct current electrolytic
capacitor, the reading will - Answerstart at zero but increase gradually for one of the
connections
/.The device used to convert direct current to alternating current is called -
Answerinverters
/.Of the following conditions, the one which is MOST likely to cause flashing or
excessive arcing from brush to brush in a motor is - AnswerExcessively high voltage on
the line
/.The currents in the armature equalizer connections in a DC generator are -
Answeralternating currents
/.A generating station has one 1000 Kw and two 2000 Kw generators. To supply 2000
Kw MOST economically, the operating conditions should be - Answerone 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. - Answer220
/.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 - Answer6
/.If the field of a shunt motor opens while running, the motor will - Answerrun 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. - Answershunt field and to the series
/.A main contributing factor to motor stator failure usually is - Answerdirt
/.The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy
loss is __________ watts. - Answer8,000
, /.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. - Answer14.4
/.Of the following motors, the one that has the best speed regulation is the motor. -
Answershunt
/.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 - Answer1080
/.Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) -
Answercan 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 - Answermotor will take a leading current
/.When transformers are to be operated in parallel, it is NOT necessary that the
transformer have the same - AnswerKVA rating
/.A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80%
when it is supplying - Answer160 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. - Answer25
/.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 -
Answershort the secondary of the transformer
/.A DC relay is rated at 6 volts and 120 ohms. This relay can be operated from a 120
volt line by connecting a ___________ ohm resistance in __________ with relay -
Answer2280: series
/.Some relays are provided with dash-pots. The FUNCTION of these dash-pots is to
provide - Answerdelayed time action
/.An ammeter has a full scale deflection for a current of 0.01 amperes and an internal
resistance of 20 ohms. In order to have the ammeter read full-scale for a current of 10
amperes and not damage its movement, a shunt should be used having a value
of__________ ohms. - Answer0.02
/.An air circuit breaker has contacts that flash. The MOST probable cause of this trouble
is that the - Answerbarriers are broken
