2A652 Volume 3 CDC Pretest
Questions and Answers
- 1.
After shutdown a motor continues turning; this is known as
- A.
Inertia
- B.
Impedance
- C.
Inductance
- D.
Eddy currents
Correct Answer
A. InertiaExplanation
After shutdown, a motor continues turning due to inertia. Inertia is the tendency of an object to resist changes in its motion. In the case of a motor, when it is suddenly turned off, the moving parts of the motor, such as the rotor, continue to spin due to their momentum. This is because the motor requires some time to come to a complete stop as the force that was driving it is no longer present.Rate this question:
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- 2.
Torque is defined as
- A.
Horsepower
- B.
Wattage
- C.
Rotational force
- D.
Opposition to applied voltage
Correct Answer
C. Rotational forceExplanation
Torque is defined as rotational force. It is the measure of the force that can cause an object to rotate around an axis. It is commonly used to describe the twisting or turning force applied to an object, such as a wrench turning a bolt. Torque is dependent on both the magnitude of the force and the distance from the axis of rotation. It is often measured in units such as Newton-meters (Nm) or foot-pounds (ft-lb).Rate this question:
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- 3.
In a series-wound DC motor, speed is controlled by the
- A.
Load
- B.
Torque
- C.
Armature
- D.
Field winding
Correct Answer
A. LoadExplanation
In a series-wound DC motor, the speed is controlled by the load. This means that the speed of the motor is influenced by the amount of mechanical resistance or load that is connected to it. As the load increases, the motor's speed decreases, and vice versa. The load torque directly affects the motor's speed by opposing or assisting the rotation of the armature. The field winding, on the other hand, is responsible for creating the magnetic field within the motor but does not directly control the speed.Rate this question:
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- 4.
Which induction motor has the highest starting torque?
- A.
Capacitive-start
- B.
Squirrel cage
- C.
Shaded pole
- D.
Split-phase
Correct Answer
A. Capacitive-startExplanation
The capacitive-start induction motor has the highest starting torque compared to the other options. This is because it uses a capacitor in the starting winding to create a phase shift between the main and starting windings, resulting in a higher starting torque. The squirrel cage, shaded pole, and split-phase induction motors have lower starting torques in comparison.Rate this question:
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- 5.
The three-phase induction motor does not require
- A.
Slip
- B.
A totor
- C.
A stator
- D.
A starting device
Correct Answer
D. A starting deviceExplanation
The three-phase induction motor does not require a starting device because it is a self-starting motor. This is because the rotating magnetic field created by the stator induces currents in the rotor, which causes it to start rotating. The slip, which is the difference between the synchronous speed of the rotating magnetic field and the actual speed of the rotor, is necessary for the motor to operate efficiently. However, a separate starting device is not needed as the motor can start on its own.Rate this question:
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- 6.
One advantage of the three-phase induction motor over a comparable single-phase unit is
- A.
Lower voltage requirement
- B.
High starting torque
- C.
A higher speed
- D.
Less weight
Correct Answer
B. High starting torqueExplanation
The advantage of a three-phase induction motor over a comparable single-phase unit is its high starting torque. This means that the motor can handle heavier loads and start them more efficiently, making it suitable for applications that require high torque at startup. The high starting torque allows the motor to quickly accelerate and overcome inertia, making it more reliable and efficient in various industrial and commercial settings.Rate this question:
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- 7.
The stator windings of a synchronous motor are wound
- A.
20 degrees apart
- B.
30 degrees apart
- C.
90 degrees apart
- D.
120 degrees apart
Correct Answer
D. 120 degrees apartExplanation
The stator windings of a synchronous motor are wound 120 degrees apart. This is because a synchronous motor requires a rotating magnetic field to operate. By winding the stator windings 120 degrees apart, the resulting magnetic field produced by the windings will have a phase difference of 120 degrees. This phase difference is necessary for the motor to synchronize with the rotating magnetic field produced by the rotor, allowing for efficient and smooth operation of the motor.Rate this question:
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- 8.
Which component is one of the major causes of failure in the DC motor?
- A.
Commutator
- B.
Slip rings
- C.
Bearings
- D.
Rotor
Correct Answer
A. CommutatorExplanation
The commutator is one of the major causes of failure in a DC motor. The commutator is responsible for transferring electrical power to the armature coil, and over time, it can wear out or become damaged. This can result in poor electrical connections, sparking, and increased friction, leading to motor failure. Regular maintenance and inspection of the commutator can help prevent these issues and ensure the smooth operation of the DC motor.Rate this question:
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- 9.
When you check the concentricity of a commutator or slip rings, look for
- A.
Wear
- B.
Pitting
- C.
Roundness
- D.
Overheating
Correct Answer
C. RoundnessExplanation
When checking the concentricity of a commutator or slip rings, it is important to look for roundness. This means that the shape of the commutator or slip rings should be circular and not distorted or irregular in any way. Roundness is crucial for the proper functioning of the commutator or slip rings as it ensures smooth contact and transfer of electrical current. If there is any deviation from roundness, it can lead to issues such as poor electrical conductivity, increased friction, and potential damage to the components. Therefore, roundness is a key factor to consider when inspecting the concentricity of a commutator or slip rings.Rate this question:
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- 10.
When using a troubleshooting chart, what are you not likely to find?
- A.
Analysys
- B.
Remedies
- C.
Symptoms
- D.
Probable causes
Correct Answer
A. AnalysysExplanation
When using a troubleshooting chart, you are not likely to find "Analysis" as it is not a typical component of a troubleshooting chart. A troubleshooting chart is designed to provide a step-by-step guide to identify and resolve problems, typically listing symptoms, probable causes, and remedies. Analysis, on the other hand, refers to the process of examining and evaluating data or information, which is not typically included in a troubleshooting chart.Rate this question:
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- 11.
The first thing you should do when troubleshooting a motor is a
- A.
Voltage check
- B.
Continuity test
- C.
Visual inspection
- D.
Current measurement
Correct Answer
C. Visual inspectionExplanation
A visual inspection is the first thing you should do when troubleshooting a motor because it allows you to quickly identify any obvious issues or abnormalities. By visually inspecting the motor, you can check for loose connections, damaged wires, burned-out components, or any other visible signs of damage or malfunction. This initial inspection can help determine if further testing or repairs are necessary, saving time and effort in the troubleshooting process.Rate this question:
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- 12.
The component most likely to be damaged by cleaning solvent is the
- A.
Brushes
- B.
Bearings
- C.
Slip rings
- D.
Commutator
Correct Answer
A. BrushesExplanation
Cleaning solvents can cause damage to the brushes in an electrical component. The solvents can dissolve the material of the brushes or cause them to become brittle, leading to their deterioration or breakage. Brushes are crucial for the proper functioning of the component as they make contact with the commutator or slip rings, transferring the electrical current. If the brushes are damaged, it can result in poor electrical contact, reduced performance, or even complete failure of the component. Therefore, it is important to handle cleaning solvents with caution to avoid damaging the brushes.Rate this question:
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- 13.
The type of injector that is operated by a rocker arm is the
- A.
Spray
- B.
Pintle
- C.
Pressure
- D.
Mechanical
Correct Answer
D. MechanicalExplanation
A mechanical injector is operated by a rocker arm. The rocker arm is responsible for opening and closing the injector valve, allowing fuel to be sprayed into the combustion chamber. This type of injector is commonly found in older vehicle models and is known for its durability and reliability. Unlike other types of injectors, such as pintle or pressure injectors, the mechanical injector does not rely on electronic components or sensors for operation. Instead, it is mechanically controlled, making it a simpler and more straightforward design.Rate this question:
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- 14.
When a lubricant reduces friction, it also reduces
- A.
Heat
- B.
Wear
- C.
Resistance
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
When a lubricant reduces friction, it also reduces heat, wear, and resistance. This is because lubricants provide a protective layer between two surfaces, allowing them to slide smoothly against each other. By reducing friction, the lubricant minimizes the generation of heat, which can cause damage to the surfaces. Additionally, the lubricant prevents wear by reducing the contact and friction between the surfaces. Lastly, lubricants help to reduce resistance, making it easier for the surfaces to move and operate efficiently. Therefore, all of the given options are correct.Rate this question:
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- 15.
Which function does a lubricant perform by constantly circulating past the air that surrounds the oil sump?
- A.
Cooling
- B.
Sealing
- C.
Cleaning
- D.
Reducing friction
Correct Answer
A. CoolingExplanation
A lubricant circulates past the air surrounding the oil sump in order to cool the system. As the lubricant flows, it absorbs heat from the engine components and carries it away, preventing overheating. This helps to maintain the optimal operating temperature and prevents damage to the engine. Cooling is an essential function of a lubricant to ensure the efficient operation and longevity of the engine.Rate this question:
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- 16.
Which component holds a large amount of coolant in close contact with a large volume of air?
- A.
Radiator cap
- B.
Thermostat
- C.
Water pump
- D.
Radiator
Correct Answer
D. RadiatorExplanation
The radiator holds a large amount of coolant in close contact with a large volume of air. As the hot coolant flows through the radiator, it releases heat to the surrounding air, which helps in cooling down the coolant. The radiator is designed with a series of tubes and fins that increase the surface area for better heat transfer. This allows for efficient cooling of the coolant before it is circulated back into the engine.Rate this question:
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- 17.
The purpose of the cooling system thermostat is to maintain correct engine
- A.
Operating temperature
- B.
Coolant temperature
- C.
System pressure
- D.
Coolant flow
Correct Answer
B. Coolant temperatureExplanation
The purpose of the cooling system thermostat is to regulate and maintain the appropriate temperature of the engine coolant. The thermostat helps to ensure that the coolant temperature remains within the optimal range for efficient engine operation. By controlling the flow of coolant, the thermostat allows the engine to warm up quickly during cold starts and helps prevent overheating by allowing coolant circulation when the engine reaches its operating temperature. This helps to protect the engine from damage and ensures optimal performance.Rate this question:
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- 18.
What is installed on a two stroke diesel engine to ensure displacement of all exhaust gases?
- A.
Blower
- B.
Intake valve
- C.
Exhaust valve
- D.
Turbulence chamber
Correct Answer
A. BlowerExplanation
A blower is installed on a two-stroke diesel engine to ensure the displacement of all exhaust gases. The blower helps in creating positive pressure in the cylinder, which helps in pushing out the exhaust gases and bringing in fresh air for the next combustion cycle. This ensures that all the exhaust gases are effectively removed from the cylinder, allowing for better engine performance and efficiency.Rate this question:
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- 19.
The maintenance procedure that is considered to be the cheapest and most effective means of reducing injection equipment problems and maintenance costs is
- A.
Correct defective components only
- B.
Rigid maintenance schedules
- C.
Periodic overhaul schedule
- D.
Preventive maintenance
Correct Answer
D. Preventive maintenanceExplanation
Preventive maintenance is the most cost-effective and efficient method of reducing injection equipment problems and maintenance costs. This approach involves regularly inspecting and servicing equipment to prevent breakdowns and identify potential issues before they become major problems. By conducting routine maintenance tasks such as cleaning, lubricating, and replacing worn parts, the likelihood of equipment failure is significantly reduced. This proactive approach helps to extend the lifespan of the equipment, improve its performance, and minimize the need for costly repairs or replacements.Rate this question:
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- 20.
The filtration step protects the diesel engine fuel system from
- A.
Blockage of airflow
- B.
Lube system malfunctions
- C.
Slipping belts on the blower
- D.
Abrasion by foreign particles
Correct Answer
D. Abrasion by foreign particlesExplanation
The filtration step in a diesel engine fuel system is necessary to protect the system from abrasion caused by foreign particles. These particles can enter the fuel system and cause damage to various components, such as the fuel injectors and fuel pump. By using a filtration step, these particles are removed from the fuel before it reaches the engine, preventing any potential abrasion and ensuring smooth operation of the fuel system.Rate this question:
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- 21.
The best step in preventing abnormal amounts of carbon, mositure, and sludge bulid-up in a diesel engine, is to
- A.
Avoid operating the engine for extended periods at no-load
- B.
Operate the unit a idle speed for ling periods of time
- C.
Drain moisture from fuel system periodically
- D.
Perform a preoperation check
Correct Answer
A. Avoid operating the engine for extended periods at no-loadExplanation
To prevent abnormal amounts of carbon, moisture, and sludge build-up in a diesel engine, it is best to avoid operating the engine for extended periods at no-load. When an engine operates at no-load, it means it is running without any external load or resistance. This can lead to incomplete combustion, which in turn causes carbon deposits and build-up of moisture and sludge in the engine. By avoiding extended periods of no-load operation, the engine can maintain proper combustion and reduce the risk of carbon, moisture, and sludge accumulation.Rate this question:
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- 22.
When performing a compression test the allowable deviation between cylinders is
- A.
25 psi
- B.
50 psi
- C.
75 psi
- D.
100 psi
Correct Answer
A. 25 psiExplanation
During a compression test, the allowable deviation between cylinders refers to the acceptable difference in compression pressure readings between individual cylinders in an engine. The correct answer of 25 psi suggests that a variance of up to 25 psi is considered acceptable between cylinders. This means that if the compression pressure readings of all cylinders fall within a range of 25 psi, the engine is considered to have balanced compression and is functioning properly.Rate this question:
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- 23.
During starting, the turbine engine is rotated up to 20 percent by the
- A.
AC generator
- B.
Starter motor
- C.
Tachometer generator
- D.
Fuel pump and control unit
Correct Answer
B. Starter motorExplanation
The starter motor is responsible for rotating the turbine engine during the starting process. It provides the initial power to get the engine moving and build up the necessary momentum for combustion to occur. The AC generator, tachometer generator, and fuel pump and control unit are not directly involved in the starting process.Rate this question:
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- 24.
In the gas turbine engine, cooling air for the transformer rectifier is provided by the
- A.
Starter motor
- B.
Cooling fan
- C.
Fuel pump and control unit
- D.
Multiple centrifugal switch assembly
Correct Answer
B. Cooling fanExplanation
The cooling air for the transformer rectifier in a gas turbine engine is provided by the cooling fan. The cooling fan is responsible for circulating air to remove heat from various components, including the transformer rectifier. This helps to prevent overheating and ensures the proper functioning of the engine.Rate this question:
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- 25.
During gas turbine engine operation, the air is accelerated by the
- A.
Impellers
- B.
Diffusers
- C.
Exducers
- D.
Deswirl ring
Correct Answer
A. ImpellersExplanation
In a gas turbine engine, the air is accelerated by the impellers. Impellers are rotating components that are responsible for drawing in and compressing the air before it enters the combustion chamber. They increase the velocity of the air by rotating at high speeds, which creates a low-pressure area and sucks in more air. This accelerated air is then directed towards the diffusers, exducers, and deswirl ring for further processing and combustion. Therefore, impellers play a crucial role in the initial acceleration of the air in a gas turbine engine.Rate this question:
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- 26.
In the operation of a turbine engine, energy is extracted from the burning gases by the
- A.
Inducer
- B.
Diffuser
- C.
Turbine wheel
- D.
Torque converter
Correct Answer
C. Turbine wheelExplanation
In the operation of a turbine engine, energy is extracted from the burning gases by the turbine wheel. The turbine wheel is connected to the compressor and is driven by the high-velocity exhaust gases. As the gases pass through the turbine wheel, they cause it to rotate, converting the kinetic energy of the gases into mechanical energy. This mechanical energy is then used to drive the compressor and other engine components, allowing the engine to continue operating efficiently.Rate this question:
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- 27.
The turbine engine's constant speed is mantained by the
- A.
Governor
- B.
Fuel regulator
- C.
Acceleration limiter valve
- D.
Acceleration stabilizer solenoid
Correct Answer
A. GovernorExplanation
The correct answer is governor. A governor is a device used in turbine engines to maintain a constant speed. It regulates the flow of fuel to the engine based on the load and speed requirements. By adjusting the amount of fuel supplied, the governor ensures that the engine maintains a consistent speed, even when the load changes. This helps to optimize the performance and efficiency of the turbine engine.Rate this question:
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- 28.
The turbine engine component that prevents fuel from accumulating in the plenum is the
- A.
Atomizer
- B.
Drain valve
- C.
Pneumatic control device
- D.
Acceleration limiter valve
Correct Answer
B. Drain valveExplanation
The drain valve is the turbine engine component that prevents fuel from accumulating in the plenum. This valve allows any excess fuel or other liquids to be drained out of the system, preventing them from building up and causing potential damage or malfunction. By removing the accumulated fuel, the drain valve helps maintain proper functioning and safety of the turbine engine.Rate this question:
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- 29.
Lubrication system pressure in the turbine engine is regulated through a
- A.
Flow check valve
- B.
Filter bypass valve
- C.
Pressure relief valve
- D.
Temperature regulator
Correct Answer
C. Pressure relief valveExplanation
The pressure relief valve is responsible for regulating the lubrication system pressure in a turbine engine. This valve is designed to open when the pressure exceeds a certain limit, allowing excess pressure to be released and preventing damage to the system. By relieving the pressure, the valve helps maintain the optimal operating conditions for the lubrication system, ensuring that the engine components are properly lubricated and protected.Rate this question:
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- 30.
During turbine engine operation, oil loss into the airflow system is prevented by the
- A.
Air-oil seals
- B.
Oil-tank baffels
- C.
Exhaust-vent line
- D.
Pressure-relief valve
Correct Answer
A. Air-oil sealsExplanation
Air-oil seals are used to prevent oil loss into the airflow system during turbine engine operation. These seals create a barrier between the oil and the airflow, ensuring that the oil remains contained within the engine and does not escape into the airflow. This helps to maintain the proper functioning of the engine and prevents any potential damage or contamination that could occur due to oil loss. Oil-tank baffles, exhaust-vent line, and pressure-relief valve do not directly address the issue of oil loss into the airflow system, making them incorrect options.Rate this question:
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- 31.
The load section of the load contol valve consists of
- A.
Chambers 1 and 2
- B.
Chambers 2 and 3
- C.
Chambers 3 and 4
- D.
Chambers 1 and 4
Correct Answer
A. Chambers 1 and 2Explanation
The load section of the load control valve consists of chambers 1 and 2. This means that these two chambers are responsible for controlling the load in the valve. The load section is an important part of the valve as it helps regulate the flow and pressure of the fluid passing through the valve. By having chambers 1 and 2 in the load section, the valve can effectively control and adjust the load based on the requirements of the system.Rate this question:
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- 32.
During a preoperation inspection of a gas turbine engine, you check the intake and exhaust for
- A.
Leakage
- B.
Excess heat
- C.
Hairline cracks
- D.
Foreign objects
Correct Answer
D. Foreign objectsExplanation
During a preoperation inspection of a gas turbine engine, it is important to check the intake and exhaust for foreign objects. This is because any foreign objects, such as debris or particles, can potentially enter the engine and cause damage to the internal components. By checking for foreign objects, the technician ensures that the engine operates smoothly and efficiently without any obstructions. This inspection helps to prevent any potential issues or malfunctions that could arise from the presence of foreign objects in the engine.Rate this question:
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- 33.
When you operate a gas turbine engine, you should
- A.
Use earplugs and muffs
- B.
Never enter the plane of rotation
- C.
Stay away from the reat of the engine
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
When operating a gas turbine engine, it is important to use earplugs and muffs to protect your hearing from the loud noise produced by the engine. Additionally, you should never enter the plane of rotation, as this can be extremely dangerous and can result in severe injuries or even death. Lastly, it is also crucial to stay away from the rear of the engine, as there may be hot exhaust gases or other hazards present. Therefore, the correct answer is "all of the above" as all three options are necessary precautions to ensure safety when operating a gas turbine engine.Rate this question:
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- 34.
Normal acceleration characteristics of the GTC include
- A.
A decrease in vibration after 35 percent
- B.
Sudden rumbling noises after 35 percent
- C.
Smooth and quiet acceleration
- D.
Burping
Correct Answer
A. A decrease in vibration after 35 percentExplanation
The correct answer is a decrease in vibration after 35 percent. This means that as the GTC accelerates, the level of vibration experienced by the vehicle decreases after it reaches 35 percent of its acceleration. This characteristic suggests that the GTC provides a smoother and more comfortable ride as it gains speed.Rate this question:
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- 35.
Before you load and after you unload the GTC, allow the engine to operate unloaded to
- A.
Decrease noise
- B.
Allow for flameouts
- C.
Reduce thermal stress
- D.
Allow for positioning of the service hose
Correct Answer
C. Reduce thermal stressExplanation
Operating the engine unloaded before loading and after unloading the GTC (Gas Turbine Compressor) helps to reduce thermal stress. When the engine is not under load, it experiences less strain and heat, which can prevent damage caused by excessive temperatures. This practice allows the engine to cool down and stabilize before being subjected to heavy loads or during shutdown, ensuring its longevity and efficient operation.Rate this question:
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- 36.
Common or requently occuring troubles in a unit, their cause, and remedies may be found in the
- A.
Historical records
- B.
Maintenance records
- C.
Troubleshooting chart
- D.
Illustrated parts breakdown
Correct Answer
C. Troubleshooting chartExplanation
A troubleshooting chart provides information about common or frequently occurring troubles in a unit, their cause, and remedies. It is a useful resource for identifying and resolving issues that may arise during the operation or maintenance of the unit. Historical records may provide some information about past troubles, but they may not be comprehensive or up-to-date. Maintenance records primarily focus on the maintenance activities performed on the unit and may not provide detailed troubleshooting information. An illustrated parts breakdown is a visual representation of the unit's components and may not include troubleshooting details. Therefore, a troubleshooting chart is the most appropriate source for finding information about common troubles, their cause, and remedies.Rate this question:
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- 37.
While troubleshooting the GTC, you find no oil pressure and the oil filter is dirty. Will changing the filter correct the problem?
- A.
Yes
- B.
No, the filter bypass valve is stuck open
- C.
No, the oil pressure relief valve is stuck open
- D.
No, the scavenge pump is not providing sufficient suction
Correct Answer
C. No, the oil pressure relief valve is stuck openExplanation
The oil pressure relief valve is responsible for regulating the oil pressure in the system. If it is stuck open, it means that it is not closing properly and allowing oil to bypass the system, resulting in no oil pressure. Changing the oil filter will not correct this problem, as it is not related to the filter itself.Rate this question:
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- 38.
Which causes gray or white smoke to pour from the exhaust stack on the GTC?
- A.
Excessive engine rpm
- B.
Fuel mixing with the airflow
- C.
Oil that enters the airflow system
- D.
Excessive engine exhaust temperature
Correct Answer
C. Oil that enters the airflow systemExplanation
When oil enters the airflow system, it can cause gray or white smoke to pour from the exhaust stack on the GTC. This is because the oil mixes with the fuel and air, resulting in the smoke being emitted from the exhaust.Rate this question:
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- 39.
Which could cause the butterfly valve to oscillate (continually open and close)?
- A.
Load valve
- B.
Hose relief valve
- C.
Pneumatic load thermostat
- D.
Rate adjustment screw
Correct Answer
C. Pneumatic load thermostatExplanation
A pneumatic load thermostat could cause the butterfly valve to oscillate (continually open and close) because it is designed to regulate the flow of air or gas based on temperature. If the thermostat is not functioning properly or is set at an incorrect temperature, it may send inconsistent signals to the butterfly valve, causing it to open and close rapidly. This can lead to unstable flow and fluctuations in pressure, resulting in the valve oscillating.Rate this question:
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- 40.
Which three things are necessary to produce an EMF mechanically?
- A.
EMF, relative motion, and magnetic field
- B.
Magnet, lines of force, and relative motion
- C.
Magnetic field, conductor, and relative motion
- D.
CEMF, conductor, and magnetic field
Correct Answer
C. Magnetic field, conductor, and relative motionExplanation
To produce an electromotive force (EMF) mechanically, three things are necessary: a magnetic field, a conductor, and relative motion between the two. The magnetic field induces a force on the conductor, causing the electrons within it to move. This movement of electrons creates an electric current, resulting in the generation of an EMF. Without any one of these three components, the production of EMF mechanically would not be possible.Rate this question:
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- 41.
The internal current produced by all generators is
- A.
AC
- B.
DC
- C.
Pulsating AC
- D.
Pulsating DC
Correct Answer
A. ACExplanation
The internal current produced by all generators is AC. Alternating current (AC) is the type of electric current that periodically reverses direction. This is because generators work on the principle of electromagnetic induction, where a coil of wire rotates in a magnetic field, creating a changing magnetic flux that induces an alternating current in the wire. Therefore, the correct answer is AC.Rate this question:
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- 42.
What result is achieved by replacing the single rotating conductor of a simple DC generator with many coils of wire wound on the same shaft?
- A.
Increased output and constant AC
- B.
Increased output and constant DC
- C.
Decreased current and constant DC
- D.
Decreased current and constant AC
Correct Answer
B. Increased output and constant DCExplanation
By replacing the single rotating conductor with many coils of wire wound on the same shaft in a simple DC generator, the result achieved is increased output and constant DC. This is because the multiple coils of wire increase the amount of current generated, leading to a higher output. Additionally, the use of DC ensures that the current flows in one direction, providing a constant flow of electricity.Rate this question:
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- 43.
What part of an AC generator provides a connection between to rotating and stationary parts?
- A.
Armature
- B.
Slip rings
- C.
Commutator
- D.
Field windings
Correct Answer
B. Slip ringsExplanation
Slip rings provide a connection between the rotating and stationary parts of an AC generator. They are conductive rings that are mounted on the rotor shaft and rotate with it. The stationary brushes press against the slip rings, allowing electrical current to pass from the rotating armature to the stationary external circuit. This connection enables the transfer of electrical energy generated in the armature to the external circuit, allowing the generator to produce alternating current.Rate this question:
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- 44.
Control of the output voltage of an AC generator is accomplished by varying the
- A.
Speed of rotation
- B.
Size of the armature
- C.
Amount of field current
- D.
Size of the field windings
Correct Answer
C. Amount of field currentExplanation
The control of the output voltage of an AC generator is achieved by varying the amount of field current. The field current creates a magnetic field within the generator, which in turn induces a voltage in the armature windings. By adjusting the amount of field current, the strength of the magnetic field can be changed, resulting in a corresponding change in the output voltage. Therefore, controlling the amount of field current allows for precise regulation of the generator's output voltage.Rate this question:
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- 45.
Output phase to phase voltage on a three-phase AC generator is always
- A.
120 volts
- B.
108 volts
- C.
208 volts
- D.
240 volts
Correct Answer
C. 208 voltsExplanation
The output phase to phase voltage on a three-phase AC generator is always 208 volts. This is because in a three-phase system, the voltage between any two phases is equal to the line-to-line voltage, which is typically 208 volts in a balanced three-phase system.Rate this question:
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- 46.
Three different loads can be supported at the same time by a
- A.
DC generator
- B.
Single-phase generator
- C.
Two-phase generator
- D.
Three-phase generator
Correct Answer
D. Three-pHase generatorExplanation
A three-phase generator is capable of supporting three different loads at the same time because it generates three separate alternating currents that are 120 degrees out of phase with each other. This allows for a balanced distribution of power to each load, ensuring efficient and stable operation. Additionally, the three-phase system provides higher power output compared to single-phase or two-phase generators, making it suitable for powering multiple devices simultaneously.Rate this question:
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- 47.
The weak points of the self-excited AC generator are the
- A.
Brushes, slip rings, and rotor
- B.
Brushes, slip rings, and commutator
- C.
Commutator, rotor, and slip rings
- D.
Brushes, cummutator, and rotor
Correct Answer
B. Brushes, slip rings, and commutatorExplanation
The weak points of a self-excited AC generator are the brushes, slip rings, and commutator. These components are prone to wear and tear over time, leading to decreased efficiency and potential malfunctioning of the generator. The brushes make contact with the commutator, which rotates with the rotor, allowing the electrical current to flow. However, the brushes and commutator can wear down due to friction, resulting in poor contact and electrical resistance. Similarly, the slip rings, which provide a continuous connection between the rotor and external circuit, can also wear down and cause issues with the generator's performance.Rate this question:
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- 48.
In a brushless AC generator, what provides the field current for the main AC generator section?
- A.
PMG
- B.
Battery
- C.
Main generator
- D.
Exciter generator
Correct Answer
D. Exciter generatorExplanation
The exciter generator provides the field current for the main AC generator section in a brushless AC generator. The exciter generator is a small generator that produces the necessary electrical power to energize the field winding of the main generator. This field current creates a magnetic field, which is essential for the generation of electricity in the main generator. The exciter generator ensures that the main generator has a constant and stable field current, allowing it to generate a steady output of AC power.Rate this question:
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- 49.
How does rectification take place in a brushless AC generator?
- A.
Chemically
- B.
Magnetically
- C.
Electrically
- D.
Mechanically
Correct Answer
C. ElectricallyExplanation
Rectification takes place in a brushless AC generator electrically. In a brushless AC generator, the rectification process involves converting the alternating current (AC) produced by the generator into direct current (DC). This is achieved by using diodes, which are electrical components that allow current to flow in only one direction. The diodes are connected in a specific configuration called a rectifier bridge, which ensures that the AC current is converted into a pulsating DC current. This rectified DC current can then be used to power various electrical devices or stored in batteries for later use.Rate this question:
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- 50.
The A/M24T-8 electrical test set is capable of testing
- A.
AC power supplies only
- B.
DC power supplies only
- C.
AC and DC power supplies
- D.
AGE generator sets only
Correct Answer
C. AC and DC power suppliesExplanation
The A/M24T-8 electrical test set is capable of testing both AC and DC power supplies. This means that it can be used to assess the functionality and performance of electrical equipment that operates on both types of power sources. It provides a comprehensive testing solution for a wide range of power supplies, making it a versatile tool for electrical testing and troubleshooting.Rate this question:
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Mar 20, 2023Quiz Edited by
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Oct 19, 2010Quiz Created by
Jnjnils
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