Stationary Engineer Electric
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 - Answer-
current lags the voltage
The power factor of a load is equal to the ____________ power divided by the
____________ power. - 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. - 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. - 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. - 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 - 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. - 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. - 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
- Answer- Water
A 600 volt cartridge fuse must have knife blade contacts if its current rating exceeds
_____________ amperes. - Answer- 60
When the magnitude of the short circuit currents in a feeder circuit must be limited,
this is USUALLY accomplished by means of - 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 - 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 - Answer-
1,200
The device commonly known as a growler is FREQUENTLY used to - 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 - Answer- start at zero but increase gradually for one of
the connections
The device used to convert direct current to alternating current is called - 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 - Answer- Excessively high
voltage on the line
The currents in the armature equalizer connections in a DC generator are - 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 - 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. - 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 - Answer- 6
If the field of a shunt motor opens while running, the motor will - 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. - Answer- shunt field and to the series
A main contributing factor to motor stator failure usually is - Answer- dirt
The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy
loss is __________ watts. - 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. - Answer- 14.4
Of the following motors, the one that has the best speed regulation is the motor. -
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 - Answer-
1080
Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) -
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 - 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 - Answer- KVA rating
A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80%
when it is supplying - 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. - 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 -
Answer- short 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 -
Answer- 2280: series
Some relays are provided with dash-pots. The FUNCTION of these dash-pots is to
provide - Answer- delayed 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. - Answer- 0.02
An air circuit breaker has contacts that flash. The MOST probable cause of this
trouble is that the - Answer- barriers are broken
The MAIN purpose of a shunt trip on a circuit breaker is to - Answer- permit the
breaker to be opened electrically from a remote location, regardless of load
conditions at the breaker
The grid-controlled gas-type electronic tube MOST often used in motor control
circuits is the - Answer- thyratron
Under normal atmospheric conditions, a pressure gauge that reads 24 inches of
mercury is indicating an absolute pressure of MOST NEARLY_____________ P.S.I.
- Answer- 26.5
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 - Answer-
current lags the voltage
The power factor of a load is equal to the ____________ power divided by the
____________ power. - 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. - 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. - 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. - 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 - 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. - 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. - 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
- Answer- Water
A 600 volt cartridge fuse must have knife blade contacts if its current rating exceeds
_____________ amperes. - Answer- 60
When the magnitude of the short circuit currents in a feeder circuit must be limited,
this is USUALLY accomplished by means of - 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 - 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 - Answer-
1,200
The device commonly known as a growler is FREQUENTLY used to - 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 - Answer- start at zero but increase gradually for one of
the connections
The device used to convert direct current to alternating current is called - 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 - Answer- Excessively high
voltage on the line
The currents in the armature equalizer connections in a DC generator are - 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 - 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. - 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 - Answer- 6
If the field of a shunt motor opens while running, the motor will - 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. - Answer- shunt field and to the series
A main contributing factor to motor stator failure usually is - Answer- dirt
The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy
loss is __________ watts. - 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. - Answer- 14.4
Of the following motors, the one that has the best speed regulation is the motor. -
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 - Answer-
1080
Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) -
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 - 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 - Answer- KVA rating
A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80%
when it is supplying - 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. - 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 -
Answer- short 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 -
Answer- 2280: series
Some relays are provided with dash-pots. The FUNCTION of these dash-pots is to
provide - Answer- delayed 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. - Answer- 0.02
An air circuit breaker has contacts that flash. The MOST probable cause of this
trouble is that the - Answer- barriers are broken
The MAIN purpose of a shunt trip on a circuit breaker is to - Answer- permit the
breaker to be opened electrically from a remote location, regardless of load
conditions at the breaker
The grid-controlled gas-type electronic tube MOST often used in motor control
circuits is the - Answer- thyratron
Under normal atmospheric conditions, a pressure gauge that reads 24 inches of
mercury is indicating an absolute pressure of MOST NEARLY_____________ P.S.I.
- Answer- 26.5
