C5 - Manage operation of electrical and electronic control equipment
Which of the following is a disadvantage of an AC generator that has a low power factor?
Unable to get maximum kilowatts from the machine
All motors on the line decrease
Current losses in all parts of the machine
The gain current increases and produces lower power factors
Lead acid battery positive plate is made-up of __________.
Lead peroxide
Lead sulphate
Copper
Zinc
Kilowatt load is divided between two DC generators operating in parallel by __________________.
€¢varying the excitation voltage
€¢adjusting the governor controls
€¢increase both prime mover speeds
€¢decreasing both prime mover speeds
When the voltage and the current in an AC circuit reach their peak value at the same time, the power factor is ?
€¢unity
€¢lagging
Infinity
€¢leading
If it is needed to convert a signal in one medium to a signal in another, such as pneumatic to electrical or pneumatic to hydraulic, what device should be applied?
Transducer
Controller
Square root converter
Transmitter
Which of the following type of motors is used where uniform speed, regardless of load, is needed?
Shunt wound motor
Series wound motor
Compound wound motor
Separately exciter motor
An assembly of a pneumatic one-way flow control valve consists of a check valve and a____
Restrictor
Cushioning valve
Pneumatic timer
Spring
The phase shift between the current and voltage vectors us due to the following except:
Power capacitor
Electric flat iron
Magnet coils
Fluorescent lamp
Reactance will cause the current in a circuit to vary only when ?
Current flows
Have resistance in the circuit
No resistance in the circuit
No current flow
What kind of directional valve whose fun
5/2-way directional control valve
One-way flow control valve
3/2-way solenoid actuated with spring return directional valve
4/2-way directional control vlave
Reducing the frequency in a capacitative circuit while holding voltage constant will result in a ?
Decrease in circuit current
Decrease in capacitive reactance
Increase in apparent power
Decrease in total impedance
In an AC generator, direct current from a separate source is passed through the windings of the rotor_____.
By means of slip rings and brushes
To minimize the danger of arc over
By means of a commutator
By means of rotating bar magnet
On some diesel-electric ships , the DC propulsion motor will only attain half speed when the generator fields are fully excited.Speeds above this are obtained by________.
Raising the generator engine speed
Decreasing excitation
Rotating brush alignment
Lowering the generator engine speed
Positive ions going to the negative electrode is called?
Cations
Anions
Electron
Proton
Ammeters and voltmeters used in sinusoidal AC power systems indicate which of the following values of the waveforms measured?
Root-mean-square value
Peak value
Maximum value
Average value
Counter EMF is measured in_______?
Volts
Ohms
Coulomb
Amps
Effects of electron movement are the same regardless of the direction of____?
Current flow
Alternating current
Cycle
Magnetic effect
Which of the following refers to a bipolar transistor which utilizes an Ntype region which is sandwiched between two P-type regions?
PNP transistor
PIN transistor
Basic transistor
NPN transistor
Why is it necessary to measure bolted bus bar joint resistance?
Because as high current flows through the bus bar, any resistance in it causes resistive heating
Because as high current flows through the bus bar, current may leak to the ground
Because the nuts and bolts could get loose over time and cause abnormally high resistance
Because the bolted joints surfaces can deteriorate and cause different resistance values over time
In general, Zener diodes can dissipate more power if its leads are___________.
Shortened
Elongated
Extended
Prolonged
An alloy of nickel and copper used for thermocouple is called?
Constantant
Steel
Alumel
Chromel
What type of level control system is fitted either on the top of the boiler drum or in a water chamber attached to a metal rod which activates magnetic switches for starting or stopping the pump or opening and closing of the feed valve?
Level control float type
Linear variable differential transformer type
Differential pressure level control type
Level control probe type
Arrange the correct sequence of procedure for measuring insulation resistance of a HV equipment as described below. I. Close the earthing switch and make sure all the conductors are earthed. II. Confirm that all the phases are dead using an approved live line tester. III. After connecting insulation resistance (IR) tester to the circuit, safety earth is tobe disconnected. IV. Insulation resistance (IR) test is applied and recorded. V. Connect the insulation resistance (IR) tester to the conductor with safety earth connection ON. VI. Disconnect the power supply to the HV equipment by opening circuit breaker and opening isolator.
VI > II > I > V > III > IV
II > I > V > VI > III > IV
VI > I > V > III > II > IV
I > II > III > VI > V > IV
Which of the method listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel?
The series field of both generators are connected in parallel
The shunt field rheostats are interconnected
The series field of both generators are connected in series
The shunt field are interconnected
The difference between the synchronous speed of an induction machine and its operating speed (slip) may be correctly expressed as __________________.
A percent of synchronous speed
Directly in revolutions per minute
A series wound motor
A decimal fraction of synchronous speed
What type of level control system where a metal rod is suspended in the boiler water drum with electrical voltage along with an ammeter included in the circuit which can be used to control starting and stopping of the feed water pump or to open the feed water valve integrated with the level alarm?
Level control probe type
Level control float type
Linear variable differential transformer type
DP transmitter level switch
What electric device is being connected between two generators of different capacities running parallel so that the running load is divided proportionally between the two?
Equalizer
Rheostat
Voltage regulator
Power relay
In paralleling of two generators, what does it indicates if the synchronizing lamps remain lighted as the synchroscope pointer approaches the zero degree position?
Two generators are in phase
The flow of power is in reverse direction
The voltage reading of incoming generator is lower than 44o volts
Two generators are in parallel
The true power indicated by the pointer movement of a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the ?
Power factor of the load
Angle of coil displacement
Inertia of the movable coil
High resistance from the load
The most common source of excitation for synchronous motors is a/an .
DC supply
Stepup transformer
Half-wave rectifier
AC supply
Pneumatic directional valve symbols consist of either letters or the numbers 1, 2, 3, 4 and 5 as per DIN ISO 5599. What does the odd numbers represent?
Exhaust lines
Working lines
Non-return lines
Quick-exhaust lines
A two-position single-point action controller has been adjusted to minimize cycling and would only be suitable for ?
Constant load conditions
Rate action only
Wide temperature fluctuations
Intermittent load conditions
Which of the following is true when a conductor reactance is compared to an alternating current relative to the flow in a resistance?
Higher
Fluctuating
Lower
The same
The loop of wire that rotates through and cut the magnetic fieldin a generator is called______.
Armature
Carbon brushes
Poles
Slip ring
In an electro-hydraulic steering gear, any change in relative position between the synchronous receiver and the follow-up gear will result in ?
A corresponding slowing or increasing of the pumped flow rate
The pump going to full stroke
Driving the rams up against the stops
Closing of the six-way valve
The total resistance of a parallel circuit is always ________.
Smaller than that of the branch with the lowest resistance
Larger than that of the branch with greatest resistance
Equal to the sum of the individual branch resistance
Unequal to the sum of the individaul branch resistance
The purpose of the commutator and brushes on a DC generator is to_____.
Convert the alternating voltage generated within the armature to a direct voltage
Transfer generated direct current voltage from the armature to the line
Reduce sparking between the armature and the carbon brushes
Provide a sliding method to excite the field
The alarm system for an engine order telegraph uses small selsyn motors attached to the indicators.The alarm sounds when the rotors are______.
Not synchronized, current is flowing, and the relays are closed
In synchronous position, no current is flowing, and the relays are closed
Not synchronized, current is flowing, and the relays are open
In synchronous position, nocurrent is flowing, and the relays are open
As the designated rudder angle is being achieved, as a result of the original command input, the steering gear follow-up mechanism is______.
In motion, providing an input to place the main pump at null stroke
In motion, providing a null input
Not in motion, thus providing a null input
In motion, providing an input to place the main pump on maximum stroke
Hydrostatic pressure of a liquid column depends on __________.
Height of the liquid column and its density
Shape of the reservoir
Only the specific gravity of the liquid
Volume of the liquid in the reservoir
In an AC synchronous motor electric propulsion plant, propeller speed is controlled by varying the_____.
Prime mover speed
Electric coupling field strength
Propulsion generator field strength
Number of energized main motor poles
What kind of directional valve whose fun
2/2-way directional control valve
3/2-way directional control valve, normally close
3/2-way directional control valve, normally open
4/2-way directional control valve
Which of the following statements correctly applies to transistors?
The three terminals are called the emitter, base, and collector.
The emitter separates the base and collector.
NDN and PNP are the two basic types of transistors.
The collector separates the emitter and base.
What kind of directional valve whose fun
4/2-way directional control valve
5/2-way single solenoid with spring return
2/2-way directional control valve
3/2-way solenoid actuated with
In a diesel electric plant, raising the generator's field excitation will cause the DC propulsion motor to .
Increase in speed
Affect generator speed only
Decrease in speed
Affect main motor speed if done in conjunction with higher generator engine speeds
The electro-pneumatic circuit layout follows the signal flow through the control chain from bottom to top. However, the electric circuit elements are numbered following the direction of signal flow from __________________.
Left to right
Right to left
Bottom to top
Top to bottom
The load sharing characteristics of two diesel generators operating in parallel are mostly dependent on their governor______.
Speed droop settings
Idle speed settings
Speed limit settings
Load limit settings
How does a puncture valve fun
It reduces the high pressure of the fuel oil by connecting the HP side to the pump body, thereby stopping the injection of the fuel.
It lifts the fuel cam follower from the cam nose so that no fuel pumping can occur
It cuts-off the HP fuel by closing the inlet ball valve using compressed air from the stop directional valve.
It introduces HP compressed air to the reversing cylinder to apply brake on the engine
The D.C. Generator where the output is used to supply the field current is called_____.
Self excited
Shunt
Compound
Separately excited
What does a low system power factor in an alternating current electrical system directly indicates ?
A large inductive load
A large resistance load
A ground in exciter field windings
A short in exciter field windings
What is the advatange of a highervoltage system as compared to a lower-voltage system?
Reduced voltage drop.
Reduced power source.
Large currents.
Lower electrical pressure.
What is the purpose of the compressed air regulator of a service unit in a pneumatic control system?
To keep the operating pressure virtually constant regardless of fluctuations in the line pressure
To regulate the oil droplets supplied to the operating line of the pneumatic system
To regulate the operating pressure according to demand of the system
To keep the primary pressure virtually constant regardless of fluctuations in the operating pressure
Why is it there is a less chance of making mistake during assembly of an integrated circuit because ?
All components are soldered together so faulty connection is less likely to occur
All components are assembled in a step-by-step manner
All components are installed far apart
All components are glued together
What determines the power factor of an electric distribution system being suplied by a single AC generator?
By components of the connected load
By generator`s rated voltage
By prime mover speed
By output frequency
The purpose of DC generator brushes is to .
Conduct electric current to an outside circuit
Convert DC current to AC current
Provide excitation to a DC generator
Neutralize armature reaction
How can a delicate component to be soldered in a circuit be protected from the heat of the soldering process?
By using a thermal shunt
By operating the soldering gun not more than 60 seconds at a time.
By coating the leads to be soldered with a light oil film.
By pre-oxidizing the leads to be soldered.
The efficiency of a diesel engine is greatest at about 80% of maximum load. If a CPP is used, at which level, in general, the propeller efficiency is greatest?
High pitch and low rpm
Low pitch and low rpm
High pitch and high rpm
Low pitch and high rpm
A semi-conductor is a material with a _____________________.
Conductivity higher than a normal isolator
Conductivity lower than a normal insulator
High conductivity at low temperatures
Conductivity higher than a normal conductor
How can you change the speed of a multi-speed, squirrel-cage induction motor operating in a fixed frequency system ?
Interchanging stator windings to another poles
Changing the RPM of the rotor flux
Reactance in the circuit must be kept to a minimum
Changing the phase sequence of the applied voltage
To avoid damage in pulling out a defective PC board connector inside the group starter panel circuit board, it should be kept at _________.
Parallel with the circuit board
An angle with the circuit board
Opposite with the circuit board
In line with the circuit board
Pneumatic directional valve symbols consist of either letters or the numbers 1, 2, 3, 4 and 5 as per DIN ISO 5599. What does the even numbers represent?
Working lines
Exhaust lines
Control lines
Non-return lines
What kind of directional valve whose function is to control the direction taken by the fluid flow such that the flow is open in one direction and simultaneously blocked in the other?
3/2-way directional control valve
4/2-way directional control valve
5/2-way directional control valve
Check valve
The four basic primary levels of an electro-pneumatic system structure are energy supply, input elements, processing elements, and _____________.
Actuators
Transducers
I/P converters
Sensors
In an electro-pneumatic control system, what component controls the passage of air signals from the input side of the element to the output side?
Directional control valve
Check valve
Actuator
Solenoid valve
What is the main reason in using an electronic megger tester essentially for Polarization Index or PI test?
Because hand-driven megger tester will not be able to give the steady test voltage for longer time
Because an electronic megger tester will give the most accurate reading
Because electronic megger tester does not require battery or external source of energy to energize
Because an electronic megger tester can handle higher voltages
The running motor will automatically stop due to the loss of power supply if the blackout occurs and it will start again even without pressing the start push button because of __________ device.
Sequential timer
Start button
Remote start circuit
Auto start circiut
Voltage generated by most AC genrators is fed from the machne to the bus by means of_____.
Direct connections from the stator
Brushes on slip rings
Slip rings on a commutator
Brushes on a commutator
A 5/2-way directional valve has its own return flow from the actuators which can be used for other control purposes. What is best suited to be controlled by this directional valve?
Double-acting cylinders
Single-acting cylinders
Hydraulic motors
Rotary pumps
Which of the following definitions best describes sensitivity as a characteristic of controller action?
The ratio of the output in response to a specified change to the input which caused it.
The control point and the value of the controlled variable corresponding to the set point.
The time difference between the input change and the output change of the controller.
The variation of the manipulated variable produced by the mode of control.
The electrolyte of Nickel Cadmium battery is ____________.
Potassium hydroxide
Sulphuric acid
Pure distilled water
Cadmium hydroxide
What kind of electrical wiring configuration of a three-phase motor in which each winding is wired end to end to form a completely closed loop circuit, and at each of the three points where the phases are connected, a lead is brought out externally?
Delta configuration
Dual-voltage configuration
Forward-reverse configuration
Wye configuration
In the starting system of a large diesel engine, what controls the opening of the remote non-return main starting valve and the cylinder starting valves?
Pilot air system
Slow-turning valve •
Fuel linkage system •
Ahead/Astern directional valves
When compared to other component in an electronic circuit, the Integrated Circuit (IC) is ____________________.
Smaller, more reliable, and often less expensive
Smaller, less reliable and less expensive
Smaller, more reliable and generally expensive
Larger, more reliable and less expensive
Current measuring instruments must always be connected in ?
Series with a circuit
Parallel with a circuit
Series-parallel with a circuit
Delta with the shunt
How is the operator ensured that he is not in contact with any unearthed conductor before insulation resistance (IR) measurement of a HV system?
Connect the insulation resistance (IR) tester to the conductor with safety earth connection ON.
Disconnect the power supply to the HV equipment by opening circuit breaker and opening isolator.
Confirm that all the phases are dead using an approved live line tester.
After connecting insulation resistance (IR) tester to the circuit, safety earth is to be disconnected.
Capacitance in an AC circuit will ?
Oppose any change in the circuit voltage
Allow current flow in the only one direction
Rectify the current
Stop current flow once the capacitors is fully charged
The conversion of a throttle command voltage to the signal necessary to achieve the desired shaft, RPM is accomplished by ________ .
Ahead or astern function generator of the throttle control circuit
Operational amplifiers in the auto rotation circuit
Ahead or astern function generator of the throttle power circuit
Feedback resistor of the summing amplifier circuit
Which directional valve can be applied to a pneumatic circuit that requires to keep or 'memorize' the last switching position unless an opposite control is given?
5/2-way double solenoid directional valve
5/2-way single solenoid with spring return
3/2-way solenoid actuated with spring return directional valve
3/2-way push button actuated with pilot air return
The alternating current produced in the generator windings is converted to direct current by the aid of ______.
Commutator and brushes
Rotor and interpoles
Field and exciter
Armature and equalizer
What type of motor wherein as the motor speed is increased, so is the load output, and whose typical applications are fans, blowers, centrifugal pumps, mixers and agitators?
Variable torque/Variable HP
Constant torque/Variable HP
Constant HP/Constant torque
Constant HP/Variable torque
Low horsepower, polyphase, induction motors can be started with full voltage by means of ?
Across-the-line starters
Compensator starter
Auto transformer starters
Primary-resistor starter
A displacer level sensor uses a _______________.
Displacer lighter than the liquid in the process vessel
Displacer heavier than the liquid in the process vessel
Displacer that varies in density from top to bottom
Displacer exactly in weight to the volume of the liquid it displaces
A multimeter may be damaged by taking a ________.
Voltage reading while in the ammeter mode
Current reading while in the voltmeter mode
Resistance reading while in the voltmeter mode
Resistance reading while in the ammeter mode
Capacitors are measured in __________________.
Farads
Watts
Ohms
Volts
In a standard motor starter panel, a motor is started by pressing the start push button switch.This energizes a starting relay and a ?
Contactor
Transformer
Starter relay
Thermal relay
The shunt used in an ammeter should be connected in .
Series with the load and in parallel with the meter movement
Series with the load and in series with the meter movement
Parallel with the load and in series with the meter movement
Parallel with the load and in parallel with the meter movement
Each hydraulic system must be fitted with a pressure relief valve downstream of the pump to prevent accidents and damage caused by excessive pressures. Spring loaded relief valves are used to adjust the working pressures and limit the operating pressures or are also employed as safety valves. What kind of relief valves are used whenever large volumes of hydraulic oils are involved?
Pilot controlled pressure relief valves
Solenoid controlled pressure relief valves
Counter-balanced valves
One-way flow control relief valves
What kind of electrical wiring configuration of a three-phase motor in which one end of each of the three phases is connected to the other phases internally, and the remaining end of each phase is then brought out externally and connected to the power line?
Wye configuration
Forward-reverse configuration
Dual voltage configuration
Delta configuration
Regarding an AC generator connected to the main electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in armature reaction are conpensated for by the______.
Voltage regulator
Phase-balance relay
Governor speed droop setting
Balance coil
In a diesel engine starting air system, from the air receiver, where is the compressed air for starting supplied first before the cylinder air starting valve?
Automatic main starting valve
Starting solenoid valve
Ahead or astern directional valve
Starting air distributor
The simplest method of controlling the terminal voltage of compoundwound DC generator iis with a_____.
Hand-operated field rheostat connected in series with the shunt field circuit
Separate exciter in a series with the sssshunt field
Balance coil diverting neutral current through the shunt field
Carbon pile regulator in series with the load
Negative ions going to the Positive electrode is called __________.
Anions
Proton
Electron
Cations
In an electro-hydraulic steering gear system, whenwill the variable displacement pump be placed on stroke?
When the helm is at any angle other than amidships
When the rudder angle is different from the position of the helm
When the six-way valve is opened
When the ram relief valves lift
Why is copper loss and iron loss less in high voltage system?
Bacause the current draw with HV is much less
Because the conductor's crosssectional area is reduced in HV installation
Because the current carrying capacity of conductor increases in HV installation
Because the copper and iron are the best conductors for HV installation
What type of motor often found on machines that have friction-type loads, such as conveyors, gear-type pumps, and load lifting equipment wherein the horsepower required increases when the speed increases?
Constant torque/Variable HP
Constant HP/Constant torque
Variable torque/Variable HP
Constant HP/Variable torque
If the relay coil is not "on" when all indicates that it should be energized with rated voltage measured across the coil is present, probably the cause would be ?
Coil is open
Auxiliary contact in series with coil is defective
Transformer is defective
Fuse is blown
A forward-biased diode acts like a switch that is___________.
Closed
Open
Capacitor
Relay
In which of the following mode does a (JFET) operates?
Depletion
Expansion
Shrinking
Contraction
Before an insulation test is carried out inside the group starter panel circuit board, the wirings leading to the sensitive circuits shall be ?
Removed
Grounded
Tested first
Taken away
Pneumatic directional valve symbols consist of either letters or the numbers 1, 2, 3, 4 and 5 as per DIN ISO 5599. What does number 1 represents?
Air source connection
Control line
Working line
Exhaust line
Which of the following indicate the temperatures in AC generator?
Standard thermometers
Imbedded thermocouples
Pyrometer
Deep well thermometers
What can be obtained in an open circuit if we use the instrument called megger tester?
Insulation efficiency •Maximum load
Current flaw
Resistance of wire
Maximum load
What is the most inefficient method of voltage reduction from the stand point of power loss?
Resistor in series with the load
Capacitor and inductor in series with the load
Capacitor in series with the load
Inductor in series with the load
A medium pressure water tube boiler uses a level differential pressure transmitter to detect the actual level inside the drum. What signals are applied to the transmitter in order to detect the process parameter?
Pressure from the HP and LP side of the steam drum
Pressure from the steam side of the boiler
Pressure from the water side of the boiler
Main steam drum and steam flow pressures
What safety device prevents the opening of the remote main starting non-return valve if the engine turning gear is engaged?
Interlock
Puncture valve
Sequence valve
Proximity switch
What is the ratio between the insulation resistance (IR) value measured after the application of the test voltage continuously for 10 minutes to the IR value measured after 1 minute of application?
Polarization Index or PI value
Grounding Index or GI
Power Loss or I2R value
Insulation Resistance or IR value
External shunts are sometimes provided in ammeters to ______________.
Prevent damage from heat generated by the shunt
Permit shunts with larger
Enable the construction of meter with a virtually unlimited range
Increase meter sensitivity
What form of power loss is the result of resistance in a distribution circuit in heating of conductors?
Line loss
Hysteresis
R drop
Line droop
The main engine reversing mechanism is tested by repeated changes from ahead to astern and vice-versa where after each change, the engine is started. What does this test provide?
Information concerning the minimum starting air pressure at which reversing and starting can be accomplished
Information on the durability of the main starting valves after successive starts
Information on how fast the main air compressors can fill the air bottles after every start
Information of how much reduction of starting air pressure at every start
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