Description : The output voltage of a 440 volt, 60 Hz AC generator is controlled by the ______________. A. load on the alternator B. load on the prime mover C. speed of the prime mover D. exciter output voltage
Last Answer : Answer: D
Description : The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the _____________. A. prime mover speed B. exciter output voltage C. load on the alternator D. number of poles
Last Answer : Answer: B
Description : The frequency of an AC generator is adjusted by means of the ____________. A. main alternator field rheostat B. exciter field rheostat C. prime mover governor control D. equalizing reactor
Last Answer : Answer: C
Description : A reverse-current relay will prevent AC generator motorization by ____________. A. automatically redirecting the load B. automatically speeding up the prime mover C. tripping the panel board main switch D. tripping the generator circuit breaker
Description : The voltage output of an AC generator is accurately controlled by _____________. A. changing the sensitivity of the prime mover to large changes in voltage B. varying the reluctance of the air gap C. varying the DC exciter voltage D. shorting out part of the armature windings
Description : A constant output voltage from an AC generator is maintained by the _____________. A. prime mover governor B. exciter generator C. voltage regulator D. reverse power relay
Description : The voltage developed by an AC generator is controlled by varying the ____________. A. speed of the prime mover B. AC excitation to the field C. DC excitation to the field D. DC excitation of the voltage regulator
Description : The standard method of controlling the output voltage of a 440 volt, 60 Hz, AC generator is accomplished by adjusting the ____________. A. prime mover speed droop B. number of poles C. alternator field excitation D. load on the alternator
Description : An alternator will fail to produce line voltage as a result of _____________. A. a closed circuit breaker B. oxidized slip rings C. improperly staggered brushes D. exciter generator failure
Description : Prior to starting an AC generator prime mover, the voltage regulator cutout switch should be placed in the __________. A. manual position B. bus neutral position C. raise voltage position D. transfer position
Last Answer : Answer: A
Description : As load is added to an AC generator provided with constant field excitation, the prime mover slows down with the effect of ____________. A. lowering frequency and lowering generated ... C. increasing frequency and lowering generated voltage D. lowering frequency and increasing generated voltage
Description : In the illustration, the contacts between terminals 26 and 27 should be closed when _________. EL-0046 A. using one generator in isochronous mode only B. using two or more generators in ... through varying loads in parallel or single operation D. the circuit breaker is closed for that generator
Description : To increase the frequency of an operating AC generator, you should ____________. A. increase the field excitation B. decrease the field excitation C. increase the number of magnetic poles D. increase the speed of the prime mover
Description : Automatic voltage regulators provided on switchboards function to _____________. A. regulate the AC load on the generator B. protect the switchboard from high voltage C. govern prime mover speed to control voltage D. vary the field excitation to the generators
Description : Etched or burned bands on the contact faces of the brushes in a direct current generator can be caused by ____________. A. high mica segments B. copper drag on the commutator C. brushes improperly positioned D. copper embedded in the brushes
Description : When paralleling two AC generators, the frequency of the machine coming online, immediately prior to closing its breaker, should be ____________. A. slightly less than the oncoming generator frequency B. the ... bus frequency C. slightly greater than the bus frequency D. the same as the bus voltage
Description : The power factor of an AC generator operating singularly is determined by the __________. A. connected load B. prime mover speed C. field excitation D. generator's rated voltage
Description : The power factor at which a paralleled AC generator operates is usually adjusted by the _____________. A. connected load B. prime mover speed C. field excitation D. generator's rated voltage
Description : If an AC generator experiences voltage failure, the cause may be _____________. A. an open in the field circuit B. the brushes shifting out of the neutral plane C. excessive locked-rotor current D. a rotating slip ring
Description : As a result of a mechanical malfunction in one of the ship's service generators operating in parallel, you must secure that generator. In order to prevent a possible overload to the ... feeder circuit breakers, the malfunctioning prime mover turbine throttle trip, and the generator circuit breaker.
Description : An AC generator operating in parallel loses its excitation without tripping the circuit breaker. This will __________. A. not affect the faulty generator due to the compensation of the other generators B. ... between the armature and the bus D. cause high currents to be induced in the field windings
Description : A DC generator is used to supply direct current in order to maintain an AC generator field and is known as a/an _____________. A. rotor B. stator C. exciter D. armature
Description : When the operating handle of a molded-case circuit breaker is in the mid-position, the circuit breaker is indicated as being ____________. A. in the 'closed' position B. in the 'opened' position C. tripped D. reset
Description : Voltage generated by most AC generators is fed from the machine to the bus by means of ____________. A. brushes on a commutator B. brushes on slip rings C. slip rings on a commutator D. direct connections from the stator
Description : The prime mover of an AC two pole main propulsion generator drives the generator at 3600 RPM. If the main propulsion motor has 80 poles, what will be the propeller speed? A. 45 RPM B. 80 RPM C. 90 RPM D. 180 RPM
Description : In an AC synchronous motor electric propulsion plant, propeller speed is controlled by varying the _____________. A. prime mover speed B. electric coupling field strength C. number of energized main motor poles D. propulsion generator field strength
Description : You are attempting to parallel two AC generators and the synchroscope pointer is revolving slowly in the fast direction. You should _____________. A. use the governor control switch to adjust the incoming ... the 0° position D. use the field rheostat to adjust the speed of the incoming machine
Description : When paralleling two AC generators, the frequency of the incoming machine immediately prior to closing its breaker should be ____________. A. controlled by placing the governor switch in the automatic ... regulator C. slightly greater than the bus frequency D. slightly less than the bus frequency
Description : A bus disconnect link is used to isolate _____________. A. one bus bar from another B. the generator circuit breaker from the bus C. different phases from the equalizer connection D. positive and negative buses from the neutral
Description : Which of the methods listed is used to start a AC generator turning? A. Residual magnetism remaining in the field poles. B. Residual magnetism remaining in the field coils. C. Residual magnetism remaining in the armature. D. Rotation by a mechanical prime mover.
Description : On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dropped out of synchronization with the propulsion generator? A. Excessive ... Tripped main motor interlocks C. Overheated crosstie busses D. Closed contact in the field circuits
Description : Three factors responsible for the change in voltage as load is applied to an AC generator are: 1) the drop in resistance in the armature circuit, 2) the change in flux, and 3) the ____________. A. armature winding speed B. inductance load drop C. coil pitch factor D. armature reactance voltage drop
Description : The voltage of an operating AC turbogenerator is raised or lowered by adjusting the _____________. A. exciter generator governor controls B. synchronizing switch C. phase sequence switch D. generator field exciter
Description : The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply
Description : The amount of voltage induced in the windings of an AC generator depends mainly on _____________. A. the number of field poles energized B. the speed at which the stator windings rotate through the magnetic field C. the strength of the magnetic field D. all of the above
Description : Undervoltage trips are frequently installed on switchboard circuit breakers to trip ____________. A. out generators in the event of severe arcing or sparking B. out generators when there is reversal of power ... , but continues to run D. out generators when there is low voltage in the main circuit
Description : You are attempting to parallel two AC generators and the synchroscope pointer stops at a position other than 0°. If you close the circuit breaker at this moment _____________. A. the incoming ... hazardous condition will be created by the incoming machine being at a higher frequency than the bus
Description : When securing an AC generator, you should FIRST ___________. A. open the generator circuit breaker B. switch the voltage regulator to 'manual' C. decrease the field excitation to minimum D. reduce the load on the unit
Description : Two paralleled alternators are operating near rated load. If one trips out mechanically, which of the listed actions should be taken FIRST? A. Restart the tripped machine immediately. B. Strip the board ... circuits. C. Start the emergency generator. D. Transfer all vital loads to the emergency bus.
Description : The division of the reactive KVA load between paralleled AC generators is initiated by the ______________. A. prime mover governors B. voltage regulators C. phase balance relay D. proportioner
Description : The division of the kilowatt load between two AC generators operating in parallel is controlled by the settings and characteristics of the _____________. A. voltage regulators B. field rheostats C. reverse power relays D. prime mover governors
Description : Kilowatt load is divided between two AC generators operating in parallel by _____________. A. adjusting the governor controls B. varying the excitation voltage C. increasing both prime mover speeds simultaneously D. decreasing both prime mover speeds simultaneously
Description : How will a molded-case circuit breaker react after it has tripped, as a result of an overloaded circuit? A. The breaker will trip again if immediately reset. B. The breaker handle will lock in ... down. D. The breaker handle cannot be moved to the OFF position until the thermal element cools down.
Description : When the operating handle of a molded case circuit breaker is in the mid-position, it indicates the circuit breaker is _____________. A. in the 'opened' position B. in the 'closed' position C. tripped D. reset
Description : You can determine if a circuit breaker is tripped by ______. A. examining the position of the handle B. checking for the warm breaker C. looking for a burned-out link D. looking for the tripped breaker light
Description : You can determine if a circuit breaker has tripped by ________________. A. examining the position of the handle B. checking for which of the breakers is warm C. looking for a burned-out link D. all of the above
Description : When the operating handle of a molded-case circuit breaker is in the mid-position, this indicates that the circuit breaker is _____________. A. on B. off C. reset D. tripped
Description : The devices labeled 'L' in the illustration are _________. EL-0003 A. load lights indicating that the generator breaker is closed and the generator is supplying power to the main bus B. ... o'clock position the lights are at their dimmest or out indicating the the generators are in phase
Description : You are attempting to parallel two AC generators, and the synchroscope pointer is revolving fast in the clockwise direction. This indicates that the frequency of the incoming machine is _____________. A. higher ... at any pointer position D. the same as the bus frequency but out of phase with it
Description : You are attempting to parallel two AC generators, and the synchroscope pointer is revolving in the fast direction. This indicates that the frequency of the incoming machine is _____________. A. higher ... the same as the bus frequency and the circuit breaker may be closed at any pointer position