1.
To change electrical energy to mechanical energy is the purpose of a
Correct Answer
D. Motor
Explanation
A motor is a device that converts electrical energy into mechanical energy. It does this by using the principle of electromagnetism, where the interaction between electric current and magnetic fields generates a force that causes the motor to rotate. This rotation can then be used to perform mechanical work, such as driving a machine or a vehicle. Generators, converters, and inverters are devices that primarily deal with the conversion or manipulation of electrical energy, but they do not directly convert it into mechanical energy like a motor does.
2.
Electrical contact between the stationary and rotating parts of a motor is the function of the
Correct Answer
D. Brushes
Explanation
The brushes in a motor are responsible for establishing electrical contact between the stationary and rotating parts. They are made of conductive material and are in constant contact with the commutator, which is mounted on the rotor. As the rotor spins, the brushes maintain contact with the commutator, allowing electrical current to flow from the stationary field windings to the rotating armature, thus enabling the motor to function properly.
3.
Torque is defined as
Correct Answer
C. Rotational force
Explanation
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 in physics and engineering to describe the twisting or turning force applied to an object. Torque is dependent on both the force applied and the distance from the axis of rotation. It is often measured in units such as Newton-meters (N-m) or foot-pounds (ft-lb).
4.
In a series-wound dierect current (DC) motor, speed is dependent on the
Correct Answer
A. Load
Explanation
In a series-wound DC motor, the speed is dependent on the load. This means that the speed of the motor will vary depending on the amount of load or resistance that is applied to the motor. As the load increases, the speed of the motor will decrease, and vice versa. The load affects the torque produced by the motor, which in turn affects the speed. Therefore, the load is a crucial factor in determining the speed of a series-wound DC motor.
5.
The relationship between slip and torque can best be described as more
Correct Answer
B. Slip causing more torque
Explanation
When there is slip in a system, it means that the actual speed of the system is different from the desired or intended speed. In the context of torque, slip causing more torque means that when there is slip, the torque produced in the system increases. This can be explained by the fact that slip causes a difference between the rotor speed and the synchronous speed in an electric motor, leading to an increase in the torque required to overcome this difference and maintain the desired speed. Therefore, slip causing more torque is the correct explanation for the relationship between slip and torque.
6.
The three-phase induction motor does not require
Correct Answer
D. A starting device
Explanation
The three-phase induction motor does not require a starting device because it operates on the principle of electromagnetic induction. When a three-phase supply is connected to the stator windings, a rotating magnetic field is produced, which induces currents in the rotor. These currents create a magnetic field in the rotor, causing it to rotate. As a result, the motor starts rotating without the need for any additional starting device such as a starter motor or capacitor.
7.
To reverse the direction of rotation of a three-phase inductive motor, you must reserve
Correct Answer
B. Any two power leads
Explanation
To reverse the direction of rotation of a three-phase inductive motor, you need to interchange any two power leads. This is because the direction of rotation of a motor is determined by the sequence of the three-phase power supply. By swapping any two power leads, the sequence is reversed, causing the motor to rotate in the opposite direction.
8.
The stator windings of a synchronous motor are spaced
Correct Answer
D. 120 degrees apart
Explanation
The stator windings of a synchronous motor are spaced 120 degrees apart. This spacing allows for a balanced and smooth operation of the motor. The 120-degree phase difference between the windings ensures that the magnetic fields produced by each winding are evenly distributed around the stator. This balanced distribution of magnetic fields helps in achieving a constant and efficient rotation of the motor's rotor. Additionally, the 120-degree spacing also helps in reducing harmonic distortions and improving the overall performance of the synchronous motor.
9.
The rotation speed of a sychronous motor is controlled by the
Correct Answer
C. Input frequency
Explanation
The rotation speed of a synchronous motor is controlled by the input frequency. The input frequency determines the number of times the magnetic field in the stator of the motor changes direction per second. As the input frequency increases, the speed of the motor also increases. Conversely, if the input frequency decreases, the motor speed decreases. Therefore, the input frequency plays a crucial role in controlling the rotation speed of a synchronous motor.
10.
During an inspection of a direct current (DC) motor, check the brushes for
Correct Answer
B. Seating
Explanation
During an inspection of a direct current (DC) motor, it is important to check the brushes for seating. Seating refers to the proper alignment and positioning of the brushes against the commutator. If the brushes are not properly seated, it can result in poor electrical contact and inefficient motor performance. This can lead to issues such as reduced power output, increased heat generation, and excessive wear on the brushes and commutator. Therefore, checking the brushes for seating is crucial to ensure optimal motor operation.
11.
When you check the concentricity of a commutator or slip rings, look for
Correct Answer
C. Roundness
Explanation
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. Roundness is crucial for proper functioning and smooth operation of the electrical contacts. If the commutator or slip rings are not round, it can lead to issues such as uneven brush wear, poor electrical contact, and increased friction. Therefore, roundness is an important factor to consider when inspecting the concentricity of a commutator or slip rings.
12.
When using a troubleshooting chart, what are you not likely to find?
Correct Answer
A. Analysis
Explanation
When using a troubleshooting chart, it is unlikely to find an "Analysis" section. A troubleshooting chart typically includes information on remedies, symptoms, and probable causes to help identify and resolve issues. The purpose of a troubleshooting chart is to guide users in diagnosing and fixing problems, rather than providing an analysis of the situation. Therefore, an "Analysis" section is not commonly included in such charts.
13.
Most troubleshooting on a motor can be done using a
Correct Answer
C. Multimeter
Explanation
A multimeter is a versatile tool used for measuring various electrical parameters such as voltage, current, and resistance. It can be used to troubleshoot motors by checking for continuity, measuring voltage across different components, and testing for proper current flow. With its ability to provide multiple functions in one device, a multimeter is a convenient and efficient tool for troubleshooting motor issues.
14.
Perform an operational check of the unit
Correct Answer
C. Before final reassembly of the enclosure
Explanation
The correct answer is to perform an operational check of the unit before final reassembly of the enclosure. This means that before putting all the parts back together, it is important to check if the unit is functioning properly. By doing this, any issues or defects can be identified and resolved before completing the reassembly process. This ensures that the unit is fully operational and ready for use once it is fully assembled.
15.
The component most likely to be damaged by poorly filtered fuel is the
Correct Answer
D. Injectors
Explanation
Poorly filtered fuel can contain impurities such as dirt, debris, and contaminants that can clog and damage the injectors. Injectors are responsible for delivering the fuel into the combustion chamber in a precise and controlled manner. If these injectors become damaged, they may not be able to properly atomize the fuel, leading to inefficient combustion, reduced engine performance, and potential engine damage. Therefore, the injectors are the component most likely to be damaged by poorly filtered fuel.
16.
The type of injector that is operated by a rocker arm is
Correct Answer
D. Mechanical
Explanation
A mechanical injector is operated by a rocker arm. The rocker arm is connected to the injector and is responsible for opening and closing the injector valve. When the rocker arm moves, it pushes down on the injector valve, allowing fuel to be injected into the engine. This type of injector is commonly found in older vehicles and is known for its simplicity and reliability.
17.
Aside from idle speed, the limiting speed governor through the use of flyweights and spring tension controls
Correct Answer
C. Maximum speed
Explanation
The limiting speed governor, using flyweights and spring tension controls, is responsible for regulating the maximum speed of a vehicle or machine. This governor mechanism restricts the speed to a predetermined limit, ensuring that it does not exceed a certain threshold. The other options, such as load speed, minimum speed, and intermediate speed, are not relevant in this context as they do not pertain to the maximum speed regulation.
18.
A lubricant performs which function when it deposits particles of dirt in the oil sump?
Correct Answer
C. Cleaning
Explanation
When a lubricant deposits particles of dirt in the oil sump, it is performing the function of cleaning. As the lubricant circulates through the engine, it picks up dirt and contaminants, which are then deposited in the oil sump. This helps to prevent the dirt from circulating further and potentially causing damage to the engine components. By removing the particles of dirt from the oil, the lubricant helps to maintain the cleanliness and efficiency of the engine, ensuring optimal performance and longevity.
19.
What component holds a large amount of coolant in close contact with a large volume of air?
Correct Answer
D. Radiator
Explanation
The radiator is the component that holds a large amount of coolant in close contact with a large volume of air. It is designed to transfer heat from the coolant to the surrounding air, allowing the coolant to cool down before it is recirculated back into the engine. This is achieved through a network of tubes and fins that increase the surface area available for heat transfer. As the coolant flows through the radiator, it releases heat to the air passing through it, helping to regulate the engine temperature and prevent overheating.
20.
Which liquid cooling system component circulates the coolant?
Correct Answer
B. Water pump
Explanation
The water pump is responsible for circulating the coolant in a liquid cooling system. It is designed to move the coolant through the system, ensuring that it reaches all the necessary components to absorb heat and maintain optimal operating temperatures. Without the water pump, the coolant would not flow, leading to overheating and potential damage to the system.
21.
One of the impellers within a blower on a diesel engine is normally driven
Correct Answer
C. From the engine crankshaft through a system of gears or a silent chain
Explanation
The impeller within a blower on a diesel engine is driven from the engine crankshaft through a system of gears or a silent chain. This means that the rotation of the crankshaft is transferred to the impeller through a mechanical connection, either a set of gears or a silent chain. This allows the impeller to spin and draw in air, which is then compressed and forced into the engine cylinders to aid in combustion. This method of driving the impeller ensures a direct and reliable power transfer from the engine's rotational motion to the blower.
22.
What must be accomplished to supercharge a diesel engine?
Correct Answer
B. Change the overlap and timing so that the intake and exhaust valves are open at the same time
Explanation
To supercharge a diesel engine, the overlap and timing of the intake and exhaust valves need to be changed so that they are open at the same time. This allows for better air intake and exhaust flow, improving the engine's efficiency and power output. By having both valves open simultaneously, more air can enter the combustion chamber, resulting in increased combustion and greater engine performance. This adjustment helps to optimize the engine's air-fuel mixture and enhance overall power delivery.
23.
The filtration step protects the diesel engine fuel system from
Correct Answer
D. Abrasion by foreign particles
Explanation
The filtration step in the diesel engine fuel system is important because it helps to prevent abrasion caused by foreign particles. These particles can enter the fuel system and cause damage to the engine components, leading to decreased performance and potential breakdowns. By using a filtration system, these particles are trapped and prevented from causing abrasion, ensuring the smooth operation and longevity of the fuel system.
24.
The best step in preventing abnormal amounts of carbon, moisture, and sludge buildup in a diesel engine, is to
Correct Answer
A. Avoid operating the engine for extended periods at no-load
Explanation
To prevent abnormal amounts of carbon, moisture, and sludge buildup in a diesel engine, it is best to avoid operating the engine for extended periods at no-load. This is because when the engine runs at no-load, it does not generate enough heat to burn off the carbon deposits and evaporate the moisture, leading to a buildup of these substances. By avoiding extended periods of no-load operation, the engine can reach higher temperatures and effectively burn off carbon, evaporate moisture, and prevent sludge buildup.
25.
When performing a compression test, measuring pounds per square inch (psi), the maximum allowable deviation between cylinders is
Correct Answer
A. 25 psi
Explanation
During a compression test, the pressure in each cylinder is measured in pounds per square inch (psi). The maximum allowable deviation between cylinders refers to the acceptable difference in pressure readings between the cylinders. In this case, the correct answer is 25 psi, which means that the pressure readings in each cylinder should not differ by more than 25 psi. This ensures that the compression levels in all cylinders are relatively balanced and indicates a healthy engine performance.
26.
If the drive shaft for the oil pump assembly in a gas turbine engine becomes sheared, what other component is rendered inoperative?
Correct Answer
B. Tachometer generator
Explanation
If the drive shaft for the oil pump assembly in a gas turbine engine becomes sheared, the tachometer generator is rendered inoperative. The tachometer generator is connected to the drive shaft and relies on its rotation to generate electrical signals that are used to measure the engine's speed. Therefore, if the drive shaft is sheared and unable to rotate, the tachometer generator will not be able to generate the necessary signals, rendering it inoperative.
27.
In the gas turbine engine, cooling air for the transformer rectifier is provided by the
Correct Answer
A. Cooling fan
Explanation
In a gas turbine engine, the cooling air for the transformer rectifier is provided by the cooling fan. The cooling fan is responsible for circulating air and preventing overheating of various components, including the transformer rectifier. It helps maintain optimal operating temperatures and ensures the efficient functioning of the engine. The other options mentioned, such as the starter motor, fuel pump and control unit, and multiple centrifugal switch assembly, are not directly involved in providing cooling air for the transformer rectifier.
28.
During gas turbine engine operation, the air is accelerated by the
Correct Answer
C. Impellers
Explanation
Impellers are rotating components in a gas turbine engine that accelerate the air. They consist of blades or vanes that increase the velocity and pressure of the incoming air. As the impellers rotate, they draw in air and force it out at a higher speed, creating a high-velocity airflow. This accelerated air is then directed towards the combustion chamber, where it mixes with fuel and ignites to produce the necessary power for the engine. Therefore, impellers play a crucial role in increasing the air velocity and facilitating the combustion process in a gas turbine engine.
29.
During operation of a turbine engine, fuel and air mixed are ignited in the
Correct Answer
B. Combustor can
Explanation
During the operation of a turbine engine, fuel and air are mixed and then ignited in the combustor can. The combustor can is a component of the engine where the combustion process takes place. It is designed to provide a controlled environment for the fuel and air mixture to burn efficiently, generating the necessary energy to power the turbine. The combustor can is specifically engineered to withstand high temperatures and pressures, ensuring the safe and effective combustion of the fuel-air mixture.
30.
In the operation of a turbine engine, energy is extracted from the burning gases by the
Correct Answer
C. Turbine wheel and exducer
Explanation
In the operation of a turbine engine, energy is extracted from the burning gases by the turbine wheel and exducer. The turbine wheel is responsible for converting the kinetic energy of the exhaust gases into mechanical energy, which is then used to drive the compressor and other components of the engine. The exducer, on the other hand, helps in reducing the pressure of the exhaust gases as they exit the turbine. Together, these components play a crucial role in extracting energy from the burning gases and powering the turbine engine.
31.
The boost pump on the gas turbine engine provides fuel to the
Correct Answer
B. Main fuel pump
Explanation
The boost pump on the gas turbine engine provides fuel to the main fuel pump. The main fuel pump is responsible for delivering the fuel to the combustion chamber, where it is mixed with air and ignited to produce the necessary power for the engine. Without the boost pump supplying fuel to the main fuel pump, the engine would not receive the proper fuel flow and the combustion process would be compromised. Therefore, the boost pump plays a crucial role in ensuring the proper functioning of the main fuel pump and the overall performance of the engine.
32.
Lubrication system pressure in the turbine engine is regulated through a
Correct Answer
C. Pressure relief valve
Explanation
The pressure in the lubrication system of a turbine engine is regulated by a pressure relief valve. This valve is designed to open and release excess pressure when it exceeds a certain limit, ensuring that the system does not become over pressurized. This helps to prevent damage to the engine components and ensures that the lubrication system operates within safe limits. The pressure relief valve acts as a safety mechanism, allowing the system to maintain optimal pressure levels and preventing any potential damage or failure.
33.
Gas turbine compressor (GTC) operation with insufficient oil pressure is prevented by the
Correct Answer
B. Oil pressure switch
Explanation
The oil pressure switch is responsible for preventing the operation of the gas turbine compressor (GTC) with insufficient oil pressure. This switch is designed to monitor the oil pressure in the system and if it falls below a certain threshold, it will send a signal to prevent the GTC from starting or running. This is crucial because operating the GTC without sufficient oil pressure can lead to damage and failure of the compressor, which can be costly to repair. Therefore, the oil pressure switch acts as a safety mechanism to ensure that the GTC operates within the required parameters.
34.
During turbine engine operation, oil loss into the airflow system is prevented by the
Correct Answer
A. Air-oil seals
Explanation
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 oil does not leak into the engine's airflow system. This is important because oil in the airflow system can cause damage to the engine components and reduce its efficiency. By using air-oil seals, the engine can maintain proper lubrication without the risk of oil contamination in the airflow system.
35.
If the gas turbine compressor (GTC) load control butterfly valve opens too slowly or too quickly, what is the most probable cause of the malfunction?
Correct Answer
B. Maladjusted rate adjustment screw
Explanation
If the gas turbine compressor (GTC) load control butterfly valve opens too slowly or too quickly, the most probable cause of the malfunction is a maladjusted rate adjustment screw. The rate adjustment screw is responsible for controlling the speed at which the valve opens or closes. If it is not properly adjusted, it can result in the valve opening too slowly or too quickly, leading to a malfunction in the GTC load control system.
36.
In the turbine engine, rupture of the rate diaphragm is prevented by the
Correct Answer
A. Adjustment screw
Explanation
The adjustment screw in the turbine engine prevents the rupture of the rate diaphragm. This suggests that the adjustment screw plays a role in regulating the pressure or flow rate within the engine, ensuring that it does not exceed the limits that could cause the diaphragm to rupture. By adjusting the screw, the operator can control the engine's performance and prevent any potential damage or failure.
37.
Prior to operating any aerospace ground equipment (AGE), you should perform
Correct Answer
A. A preoperational inspection
Explanation
A preoperational inspection should be performed prior to operating any aerospace ground equipment (AGE). This inspection ensures that the equipment is in proper working condition and ready for use. It involves checking various components and systems of the equipment to identify any potential issues or malfunctions. By conducting a preoperational inspection, operators can ensure the safety and efficiency of the equipment before using it. This helps prevent accidents, damage to the equipment, and promotes smooth operations.
38.
During a preoperational inspection of a gas turbine engine, you should check the intake and exhaust for
Correct Answer
D. Foreign objects
Explanation
During a preoperational inspection of a gas turbine engine, it is important to check the intake and exhaust for foreign objects. This is because foreign objects, such as debris, dust, or small particles, can obstruct the airflow and cause damage to the engine. These objects can also lead to inefficient combustion and reduced engine performance. Therefore, it is necessary to inspect and remove any foreign objects to ensure the proper functioning of the engine. Checking for leakage, excess heat, and hairline cracks are also important, but in this case, the primary concern is foreign objects.
39.
Normal acceleration characterisitics of the gas turbine compressor (GTC) include
Correct Answer
B. A decrease in vibration after 35%
Explanation
The correct answer is a decrease in vibration after 35%. This means that as the gas turbine compressor (GTC) accelerates, there is a noticeable reduction in the level of vibration. This characteristic indicates that the GTC is operating smoothly and efficiently, without any excessive vibrations that could potentially cause damage or affect performance.
40.
Before you load and after you unload the gas turbine compressor (GTC), allow the engine to operate unloaded to
Correct Answer
C. Reduce thermal stress
Explanation
Operating the engine unloaded before loading and unloading the gas turbine compressor (GTC) helps reduce thermal stress. This is because running the engine without any load allows it to cool down gradually, preventing sudden temperature changes that can cause thermal stress and potential damage to the engine components. By reducing thermal stress, the engine's longevity and performance can be improved.
41.
When you operate a unit to determine the validity of an entry on the maintenance record form, what step in effective troubleshooting are you performing?
Correct Answer
D. Verification
Explanation
When you operate a unit to determine the validity of an entry on the maintenance record form, you are performing the step of verification in effective troubleshooting. Verification involves checking and confirming the accuracy and reliability of the information or data provided. In this context, it means ensuring that the entry on the maintenance record form is correct and valid by operating the unit and cross-checking the information.
42.
While troubleshooting the gas turbine compressor (GTC), if you discover there is no oil pressure and the oil filter is dirty, changing the oil filter will not correct the problem because the
Correct Answer
B. Oil pressure relief valve is stuck open
Explanation
If the oil pressure relief valve is stuck open, it means that the valve is not closing properly, causing the oil pressure to be released instead of building up. Changing the oil filter will not correct this problem because the issue lies with the relief valve, not the filter itself. Therefore, even with a new filter, the oil pressure will still not be maintained.
43.
If no oil pressure is available from the main oil pump assembly on the gas turbine compressor (GTC), you should replace the
Correct Answer
B. Entire assembly
Explanation
If no oil pressure is available from the main oil pump assembly on the gas turbine compressor (GTC), replacing the entire assembly would be the appropriate action. This is because if there is no oil pressure, it indicates a failure or malfunction in the oil pump assembly as a whole, rather than just a specific component like the flow check valve or filter bypass relief valve. Therefore, replacing the entire assembly would ensure that the issue is resolved and that the GTC receives the necessary oil pressure for proper functioning.
44.
Which causes gray or white smoke to pour from the exhaust stack on the gas turbine compressor (GTC)?
Correct Answer
C. Oil that enters the airflow system
Explanation
When oil enters the airflow system of a gas turbine compressor (GTC), it can cause gray or white smoke to pour from the exhaust stack. This is because the oil mixes with the airflow and is burned along with the fuel, resulting in the smoke. Excessive engine revolutions per minute (rpm) and engine exhaust temperature may cause other issues, but they are not directly related to the smoke pouring from the exhaust stack.
45.
In the gas turbine compressor (GTC), if large amounts of oil are forced through the air-oil seals, the most probable cause is a defective
Correct Answer
B. Scavenge pump
Explanation
If large amounts of oil are forced through the air-oil seals in the gas turbine compressor (GTC), the most probable cause is a defective scavenge pump. The scavenge pump is responsible for removing excess oil from the GTC and returning it to the oil tank. If the scavenge pump is defective, it may not be able to properly remove the excess oil, causing it to be forced through the air-oil seals. This can lead to oil leakage and potential damage to the GTC.
46.
Which could cause the butterfly valve to oscillate (continually open and close)?
Correct Answer
D. Pneumatic load thermostat
Explanation
A pneumatic load thermostat is a device that controls the flow of air to a system based on the temperature. If the thermostat is not functioning properly, it may cause the butterfly valve to oscillate, continuously opening and closing. This could happen if the thermostat is sending incorrect signals to the valve, causing it to react in an unstable manner.
47.
Which three things are necessary to produce an electromotive force (EMF) mechanically?
Correct Answer
C. Magnetic field, a conductor, and relative motion
Explanation
To produce an electromotive force (EMF) mechanically, three things are necessary. Firstly, a magnetic field is required, as it is the presence of a magnetic field that induces the generation of an EMF. Secondly, a conductor is needed to allow the flow of electrons and create a potential difference. Finally, relative motion between the magnetic field and the conductor is necessary to generate the EMF. This relative motion causes the magnetic field to cut across the conductor, resulting in the production of an EMF.
48.
To increase the output of a generator, you must increase the
Correct Answer
C. Strength of the magnetic field
Explanation
To increase the output of a generator, you must increase the strength of the magnetic field. This is because the strength of the magnetic field determines the amount of induced current in the conductor, which in turn determines the output of the generator. By increasing the strength of the magnetic field, more lines of force will cut across the conductor, resulting in a higher induced current and therefore a higher output.
49.
What result is achieved by replacing the single rotating conductor of a simple direct current (DC) generator with many coils of wire wound on the same shaft?
Correct Answer
B. Increased output and almost constant DC
Explanation
By replacing the single rotating conductor with many coils of wire wound on the same shaft, the output of the DC generator is increased. This is because the multiple coils increase the amount of wire and therefore the amount of current that can be generated. Additionally, the DC output remains almost constant because the coils are all wound on the same shaft, ensuring a consistent flow of current.
50.
The rotor of an alternating current (AC) generator consists of the slip rings and
Correct Answer
A. Armature
Explanation
The rotor of an AC generator consists of the armature. The armature is the rotating part of the generator that is responsible for producing the AC voltage. It is made up of a coil of wire that is connected to the slip rings. As the rotor spins, the magnetic field from the stator windings induces an alternating current in the armature coil, generating the electrical power. The other options, such as the starter coil and voltage regulator, are not directly related to the rotor of the generator.