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Electrical Propulsion & Generator MCQ | Marine Geek
Boost your marine electrical technology knowledge with our comprehensive set of MCQ questions. Perfect for exam preparation and self-assessment, our questions cover all essential topics. Start practising now!
Q & AELEC
Marine Geek
6 min read
What type of system is referred to as an electric propulsion drive system in which the propulsion generator only supplies power to the propulsion motor?
an integrated system
a dedicated system
a composite system
a multi-purpose system
An electric propulsion drive system in which the propulsion generator supplies power to both the propulsion motor and ship service loads is referred to as what type of system?
an integrated system
a dedicated system
a composite system
a multi-purpose system
In a diesel electric plant, raising the generator's field excitation current will have what effect on the propulsion motor speed?
increase in speed
decrease in speed
affect generator speed only
affect main motor speed if done in conjunction with higher generator engine speeds
Propulsion AC generators creating 4160 VAC use transformers to provide nominal y 120 VAC to the automatic voltage regulator. What is the turn ratio of this step-down transformer?
4:1
1:4
35:1
40:1
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 propel er speed?
45 RPM
80 RPM
90 RPM
180 RPM
What equipment for modern SCR rectified DC propulsion drive systems is usually included in the package?
propulsion generators which produce DC power that is converted to AC power for the propulsion motor
propulsion generators which produce DC power that is directly delivered to the series wound DC propulsion motor
propulsion generators which produce AC power that is directly delivered to the synchronous AC propulsion motor
propulsion generators which produce AC power that is converted to DC power for the shunt wound DC propulsion motor
Which statement is TRUE concerning electric propulsion drives?
The propeller speed and direction of rotation are easily controllable.
Lower transmission losses compared to other types of propulsion drives.
Lack of flexibility of arrangement between the prime mover and motor.
Inability to be utilized as a source of ship's service power.
Which of the following statements is TRUE concerning Azipod propulsion systems?
The pod assembly swivels on a horizontal axis.
The system integrates propulsion and steering into one function.
The system requires the need for a separate rudder.
The system requires the use of a controllable pitch propeller.
What statement is true concerning SCR power converters as used on diesel-electric propulsion drive systems?
The propulsion generator is an AC machine, whereas the propulsion motor is a DC machine.
The propulsion generator is a DC machine, whereas the propulsion motor is an AC machine.
The propulsion generator and propulsion motor are both AC.
The propulsion generator and propulsion motor are both DC machines.
What is the operating function of a cyclo converter (CCV) as a static power converter used in electric propulsion motor drives?
provides adjustable frequency to power an ac propulsion drive motor
converts ac power to dc power in a dc propulsion drive system
converts dc power to ac power in an ac propulsion motor
provides constant frequency output power to an ac propulsion drive motor
What is the major advantage of a diesel electric propulsion plant over other drive systems?
low cost and weight
excellent propulsion manoeuvrability
less maintenance
lower fuel consumption
The propulsion motor most often utilized in an ac drive system operating in the moderate to high power range is of what type?
squirrel cage induction type
synchronous type with wound field
wound rotor induction type
split phase induction type
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 propeler speed?
45 RPM
80 RPM
90 RPM
180 RPM
How is the main shaft rotation on an AC diesel-electric propulsion vessel normally reversed?
increasing the generator frequency
decreasing the generator frequency
reversing any two phases leads to the motor
reversing the prime mover rotation
What statement is TRUE concerning the Azipod propulsion system?
It is an electric drive system using water jets.
It is an electric drive system that incorporates a DC motor.
It is an electric drive system in which the motor drives a controllable pitch propeller (CPP).
It is an electric drive system where the propulsion motor is installed in a submerged housing capable of swivelling.
Emergency generators are required to have specific safety shutdowns, including prime mover Overspeed. If a direct coupled emergency diesel generator's rated rpm is 1200, what is the maximum setting of the Overspeed trip device allowed?
1260 rpm
1320 rpm
1380 rpm
1440 rpm
In response to a loss of normal power or a simulated test, when will the emergency loads automatically be transferred to the emergency diesel generator?
when the potential from the emergency generator reaches 85 to 95 percent of its normal value
when the electric potential of the ship's service generators drops 15 to 40 percent below normal value
as soon as it is started
when the electric potential of the ship's service generators drops to 85 to 95 percent of the normal value
By what means is a diesel driven emergency generator prevented from being parallel with the ship's service generators?
an electrical interlock system
an automatic paralleling trip switch
the synchronizing oscilloscope
the reverse current relay
Emergency generators are required to automatically start upon a loss of normal supply voltage, In conducting a test of the emergency generator automatic start function, if the normal system supply voltage is 450 VAC, to what value would the normal supply voltage have to drop trigger the automatic starting of the emergency generator?
The voltage must drop to 247.5 VAC.
The voltage must drop to 270.0 VAC.
The voltage must drop to 382.5 VAC.
The voltage must drop to within a range from as low as 270 VAC to as high as 382.5 VAC.
Upon failure of the normal power supply, by what means is the emergency generator is placed on the line and connected to the emergency bus?
bus tie feeder
automatic bus transfer device
line connection feeder
power failure alarm bus
Which of the following statements is true concerning all rotating-field three-phase emergency alternators?
Each has three separate but identical, interconnected stator windings (one for each phase) acted on by one system of rotating magnets.
Each has one stator winding acted on by three separate but identical, interconnected systems of rotating magnets (one for each phase).
Each has one stator winding acted on by one system of rotating magnets.
Each has three separate but identical, interconnected stator windings (one for each phase) acted on by three separate but identical, interconnected systems of rotating magnets (one for each phase).
What is true concerning the installation of batteries used for EMERGENCY GENERATOR starting?
be located in a locker on the weather deck
be located close to the engine
have sufficient capacity to provide at least 50 starts consecutively without recharging
only be of the nickel alkaline type
What is the standard procedure for maintaining the charge in an emergency diesel starting battery by trickle charge?
continuously
at least once each week
whenever the charge falls to 75% of full charge
whenever the electrolyte-specific gravity falls to 1.250 or lower
The 24-volt DC bus on the emergency switchboard is used to supply power to what system or equipment?
general alarm and vital communication systems
steering gear power unit motors
main lighting system
propulsion engine lube oil pump motors
Emergency generators are required to automatically start upon a loss of normal supply voltage, In conducting a test of the emergency generator automatic transfer of load function, what is the maximum amount of time allowed for the automatic transfer of load to the emergency generator?
15 seconds
30 seconds
45 seconds
60 seconds
The "soft" insulation of practically all electrical machinery uses asphalt binders which reduces the potentially harmful effects of vibration. What property associated with this type of insulation must be kept in mind?
resistance to moisture absorption
tendency to absorb moisture
asbestos composition
tendency to crack
What is, the minimum number of consecutive cranking cycles an emergency diesel generator starting system must be capable of providing?
two cycles
three cycles
six cycles
eight cycles
Why is the motorization of an AC generator undesirable?
The generator will be damaged when it reverses its rotation.
It puts an excessive load on the bus.
High voltage pulses may damage the commutator.
The prime mover will be damaged when it reverses its rotation.
Why should rotor-to-stator air gap readings be taken periodically on electrical generation equipment?
determine the amount of varnish that can be applied to correct insulation problems
determine the condition of the bearings
provide for the correct proper tightening of the field coil bolts and correct lateral adjustment of the field coils
increase machine efficiency
You are testing the insulation in an AC generator with a megohmmeter. What would be the indication of a resistance value associated with dry, clean winding?
the resistance will continue to rise as the test potential is maintained, becoming fairly steady as the leakage current stabilizes
the resistance will remain constant as the temperature of the windings increases
the resistance will continue to drop as the potential is maintained, becoming fairly steady after 5 to 7 minutes
the resistance will stabilize after approximately 2 to 4 minutes of fluctuation