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 uses the principle of electromagnetism to generate a rotating motion, which can be used to perform mechanical work. In contrast, a generator is used to convert mechanical energy into electrical energy, a converter is used to change the form of electrical energy, and an inverter is used to convert DC (direct current) to AC (alternating current) or vice versa. Therefore, the purpose of changing electrical energy to mechanical energy is achieved by a motor.
2.
Electrical contact between the stationary and rotating parts of a motor is the function of the
Correct Answer
D. Brushes.
Explanation
The function of brushes in a motor is to provide electrical contact between the stationary and rotating parts. Brushes are typically made of carbon or graphite and are in constant contact with the commutator, which is connected to the rotating part of the motor. As the commutator spins, the brushes maintain contact, allowing the flow of electrical current from the power source to the motor's windings. This electrical contact is essential for the motor to function properly and generate the necessary torque to drive the motor.
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. Torque is calculated by multiplying the force applied to an object by the distance from the axis of rotation. It is commonly used in physics and engineering to describe the twisting or turning effect produced by a force.
4.
In a series-wound direct current (DC) motor, speed is dependent on the
Correct Answer
A. Load.
Explanation
In a series-wound direct current (DC) motor, the speed is dependent on the load. This means that as the load on the motor increases, the speed of the motor decreases. This is because the torque produced by the motor is directly proportional to the current flowing through the armature, and as the load increases, more current is required to maintain the same torque. Therefore, the speed of the motor decreases to accommodate the increased load.
5.
The relationship between slip and torque can best be described as more
Correct Answer
B. Slip causing more torque.
Explanation
When there is more slip between the rotating and stationary parts of a machine, it causes an increase in the torque generated. This is because slip represents the difference in speed between these parts, and the greater the slip, the greater the relative motion and the resulting torque. Therefore, slip causing more torque is the best description of 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 is a self-starting motor. It uses the principle of electromagnetic induction to generate a rotating magnetic field in the stator, which then induces currents in the rotor. These currents create a magnetic field in the rotor, causing it to rotate and start the motor. Therefore, there is no need for any external starting device like a starter motor or a capacitor to initiate the motor's operation.
7.
To reverse the direction of rotation of a three-phase inductive motor, you must reverse
Correct Answer
B. Any two power leads.
Explanation
To reverse the direction of rotation of a three-phase inductive motor, you must reverse any two power leads. This is because the direction of rotation is determined by the sequence of the phase currents. By reversing any two power leads, the sequence of the phase currents is also reversed, resulting in a change in the direction of rotation of the motor. Reversing all three phases or reversing only the A and B phases or B and C phases would not achieve the desired change in rotation 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 is because a synchronous motor is designed to produce a rotating magnetic field in the stator. In order to achieve a smooth and continuous rotation, the stator windings are evenly spaced around the stator core. A spacing of 120 degrees ensures that the magnetic field produced by each winding overlaps and combines effectively, resulting in a rotating magnetic field that can drive the rotor of the motor.
9.
The rotation speed of a synchronous motor is controlled by the
Correct Answer
C. Input frequency.
Explanation
The rotation speed of a synchronous motor is controlled by the input frequency. This is because the synchronous motor operates based on the principle of synchronism, where the rotor rotates at the same speed as the rotating magnetic field produced by the stator. The input frequency determines the speed of the rotating magnetic field, and therefore, the speed at which the rotor rotates. By changing the input frequency, the rotation speed of the synchronous motor can be adjusted.
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 contact of the brushes with the commutator, which is crucial for the motor's efficiency and performance. If the brushes are not properly seated, it can lead to poor electrical contact, increased resistance, and potential damage to the commutator. Therefore, checking the brushes for seating ensures that they are correctly positioned and making optimal contact with the commutator, allowing the motor to function effectively.
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, the focus should be on roundness. This means examining whether the shape of the commutator or slip rings is perfectly circular or not. If there are any irregularities or deviations from a round shape, it could indicate potential issues with the equipment. Wear, pitting, and overheating are also important factors to consider when inspecting commutators or slip rings, but in this case, the correct answer specifically relates to checking for roundness.
12.
When using a troubleshooting chart, what are you not likely to find?
Correct Answer
A. Analysis.
Explanation
When using a troubleshooting chart, you are not likely to find analysis. A troubleshooting chart is a tool used to systematically identify and resolve issues or problems. It typically provides a step-by-step process to follow, listing symptoms, probable causes, and remedies. The purpose of a troubleshooting chart is to guide the user through the problem-solving process by providing a structured approach. Analysis, on the other hand, involves a deeper examination and evaluation of the problem, which may require additional tools or techniques beyond what a troubleshooting chart offers.
13.
Most troubleshooting on a motor can be done using a
Correct Answer
C. Multimeter.
Explanation
A multimeter is a versatile tool that can measure various electrical properties 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 resistance values. A megger is specifically designed to measure insulation resistance and may not provide all the necessary measurements for motor troubleshooting. A growler is used to detect faults in the windings of a motor, but it is not as commonly used or versatile as a multimeter. A clamp-on ammeter measures current, which can be useful for troubleshooting motor issues, but it may not provide all the necessary measurements for a comprehensive diagnosis. Therefore, a multimeter is the most suitable tool for troubleshooting motors.
14.
Perform an operational check of the unit
Correct Answer
C. Before final reassembly of the enclosure.
Explanation
The correct answer is "before final reassembly of the enclosure." This means that the operational check should be performed after removing the defective part and before putting the unit back together. Performing the check at this stage ensures that any issues or problems can be identified and addressed before the enclosure is fully assembled, making it easier to fix any potential problems.
15.
The component most likely to be damaged by poorly filtered fuel is the
Correct Answer
D. Injectors.
Explanation
Poorly filtered fuel can contain contaminants such as dirt, debris, or water that can cause damage to the fuel injectors. The injectors are responsible for delivering the fuel into the combustion chamber in a precise and controlled manner. If these injectors become clogged or damaged due to poor filtration, they may not be able to spray the fuel properly, leading to inefficient combustion 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
The correct answer is mechanical. This is because injectors operated by a rocker arm are typically mechanical injectors. These injectors use a mechanical linkage, such as a rocker arm, to open and close the injector valve. This type of injector is commonly found in older diesel engines and relies on the mechanical movement of the rocker arm to control the fuel injection process.
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, which utilizes flyweights and spring tension controls, is responsible for regulating the maximum speed of a system. It ensures that the speed does not exceed a certain threshold, preventing any potential damage or malfunction that could occur at higher speeds. Therefore, the correct answer is maximum speed.
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. This means that the lubricant is removing or carrying away the dirt particles from the engine components and depositing them in the oil sump. This helps to prevent the dirt particles from causing damage or increasing friction within the engine, ensuring that the engine operates smoothly and efficiently.
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 holds a large amount of coolant in close contact with a large volume of air. It is designed to dissipate heat from the coolant by transferring it to the surrounding air. The radiator consists of a series of tubes and fins that allow the coolant to flow through them, while the air passes over the fins, facilitating the exchange of heat. This design maximizes the surface area of contact between the coolant and air, allowing for efficient cooling of the engine.
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 components that need to be cooled. The water pump creates the necessary pressure to push the coolant through the system, allowing it to absorb heat from the components and carry it away. Without the water pump, the coolant would not be able to circulate effectively, resulting in inefficient cooling and potentially causing the system to overheat.
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 typically driven from the engine crankshaft through a system of gears or a silent chain. This method allows for a direct connection between the engine and the blower, ensuring efficient power transfer and synchronization between the two components. The gears or silent chain provide a reliable and durable means of transmitting power from the crankshaft to the impeller, allowing the blower to effectively circulate air or fuel mixture within the engine.
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, increasing the engine's power and efficiency. By having the valves open simultaneously, more air can be brought into the combustion chamber, resulting in improved combustion and increased horsepower. This modification helps to optimize the engine's performance and maximize its power output.
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 designed to prevent the fuel system from being damaged by foreign particles. These particles can cause abrasion and wear on the engine components, leading to decreased performance and potential breakdowns. By filtering out these particles, the fuel system is protected from any potential damage and ensures smooth operation of the engine.
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 without any load, it operates at lower temperatures which can lead to incomplete combustion. Incomplete combustion can result in carbon deposits, moisture condensation, and sludge formation in the engine. Therefore, avoiding extended periods of no-load operation helps maintain higher operating temperatures and promotes complete combustion, reducing the likelihood of carbon, moisture, and 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
When performing a compression test, the maximum allowable deviation between cylinders is 25 psi. This means that the pressure reading for each cylinder should not differ by more than 25 psi. If the deviation exceeds this limit, it could indicate a problem with the engine, such as worn piston rings or valves. Therefore, it is important to ensure that the compression levels are relatively consistent across all cylinders.
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, it means that the oil pump assembly will not be able to function properly. The tachometer generator, which is responsible for measuring the rotational speed of the engine, relies on the oil pump assembly to operate. Therefore, if the drive shaft is sheared, the tachometer generator will also become inoperative as it won't receive the necessary input from the oil pump assembly.
27.
In the gas turbine engine, cooling air for the transformer rectifier is provided by the
Correct Answer
A. Cooling fan.
Explanation
The cooling air for the transformer rectifier in a gas turbine engine is provided by the cooling fan. The cooling fan helps to regulate the temperature of the transformer rectifier by circulating air and preventing overheating. This ensures that the transformer rectifier operates efficiently and avoids any potential damage due to excessive heat.
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 are responsible for accelerating the air. They are typically located in the compressor section of the engine and play a crucial role in compressing the incoming air before it enters the combustion chamber. By rotating at high speeds, the impellers create a high-pressure area, which causes the air to be accelerated and compressed. This increased pressure and velocity of the air are essential for efficient combustion and overall engine performance. Therefore, impellers are the correct answer for this question.
29.
During operation of a turbine engine, fuel and air are mixed and ignited in the
Correct Answer
B. Combustor can.
Explanation
During the operation of a turbine engine, fuel and air are mixed and ignited in the combustor can. The combustor can is a chamber where the fuel and air mixture is ignited, creating a high-energy combustion process. This combustion produces hot gases that expand and flow through the turbine, generating thrust or power. The combustor can is designed to withstand high temperatures and pressures, ensuring efficient combustion and safe operation of the turbine engine.
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 a turbine engine, the energy from the burning gases is extracted by the turbine wheel and exducer. The turbine wheel is responsible for converting the kinetic energy of the gases into rotational energy, which is then used to power the compressor and other components of the engine. The exducer, on the other hand, helps to direct the flow of exhaust gases out of the engine. Together, these components play a crucial role in extracting energy from the burning gases and ensuring the efficient operation of 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 is responsible for supplying fuel to the main fuel pump. The main fuel pump then further pressurizes the fuel and delivers it to the combustion chamber. The fuel atomizer is not directly supplied by the boost pump, and the fuel air mixture valve is not mentioned in the context of fuel supply. Therefore, the main fuel pump is the correct answer as it receives fuel from the boost pump and ensures proper fuel delivery to the combustion chamber.
32.
Lubrication system pressure in the turbine engine is regulated through a
Correct Answer
C. Pressure relief valve.
Explanation
The lubrication system pressure in a turbine engine is regulated through a pressure relief valve. This valve is designed to open when the pressure exceeds a certain limit, allowing excess oil to be released and relieving the pressure. This helps to prevent damage to the engine components and ensures that the lubrication system operates within safe parameters. The flow check valve, filter bypass valve, and temperature regulator are not directly responsible for regulating the lubrication system pressure.
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 gas turbine compressor (GTC) operation with insufficient oil pressure. It is designed to monitor the oil pressure and signal the system to shut down if the pressure falls below a certain threshold. This is crucial for the proper functioning and protection of the GTC, as insufficient oil pressure can lead to damage and failure of the compressor. The oil pressure switch acts as a safety mechanism to ensure that the GTC only operates when the oil pressure is at an appropriate level.
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 system. This is important because oil in the airflow can cause damage to the engine components and affect its performance. The air-oil seals help to maintain the integrity of the oil system and ensure that oil is properly contained within the engine.
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 butterfly valve opens or closes. If it is not properly adjusted, it can result in an incorrect rate of opening or closing, leading to the valve opening too slowly or too quickly. This can cause issues with the overall operation and efficiency of the gas turbine compressor.
36.
In the turbine engine, rupture of the rate diaphragm is prevented by the
Correct Answer
A. Adjustment screw.
Explanation
The adjustment screw is responsible for preventing the rupture of the rate diaphragm in a turbine engine. It is likely that the adjustment screw is used to control the pressure or flow rate of a fluid, ensuring that it remains within safe limits and preventing any excessive pressure that could cause the diaphragm to rupture. The other options, such as the actuator regulator, rate metering valve, and rate diaphragm return spring, do not directly address the prevention of rupture in the rate diaphragm.
37.
Prior to operating any aerospace ground equipment (AGE), you should perform
Correct Answer
A. A preoperational inspection.
Explanation
Before operating any aerospace ground equipment (AGE), it is important to perform a preoperational inspection. This inspection allows you to check the equipment for any potential issues or malfunctions before use. It ensures that the equipment is in proper working condition and ready for operation. By conducting a preoperational inspection, you can identify and address any problems or concerns, ensuring the safety and efficiency of the equipment during operation.
38.
During a preoperational inspection of a gas turbine engine, you 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 enter the engine and cause damage to the internal components. It is necessary to remove any foreign objects to ensure the engine operates smoothly and efficiently. Checking for leakage, excess heat, and hairline cracks are also important aspects of the inspection, but in this case, the primary concern is foreign objects.
39.
Normal acceleration characteristics of the gas turbine compressor (GTC) include
Correct Answer
B. A decrease in vibration after 35 percent.
Explanation
The correct answer is "a decrease in vibration after 35 percent." This suggests that the normal acceleration characteristics of the gas turbine compressor (GTC) involve a reduction in vibration levels after reaching 35 percent of its operational capacity. This decrease in vibration indicates a smoother and more stable acceleration process, which is desirable for the efficient and reliable operation of the GTC.
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
Before loading and unloading the gas turbine compressor (GTC), it is necessary to allow the engine to operate unloaded to reduce thermal stress. This is because operating the engine without any load helps in preventing excessive heat buildup and reduces the risk of thermal stress on the components. By reducing thermal stress, the engine's lifespan can be prolonged, and potential damage or failures can be avoided.
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 confirming the accuracy or truthfulness of information or data. In this context, it means checking the entry on the maintenance record form to ensure its validity and correctness. This step helps in ensuring that the maintenance records are accurate and reliable for future reference and decision-making.
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 there is no oil pressure and the oil filter is dirty, changing the oil filter will not correct the problem because the oil pressure relief valve is stuck open. The oil pressure relief valve is responsible for regulating the oil pressure in the system. If it is stuck open, it will allow oil to bypass the filter, resulting in low or no oil pressure. Changing the oil filter will not address the issue with the relief valve and therefore will not solve the problem.
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 there is no oil pressure available from the main oil pump assembly on the gas turbine compressor (GTC), it indicates a complete failure of the oil pump assembly. In such a situation, replacing the entire assembly is necessary to ensure that the oil pressure is restored and the GTC can function properly.
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 burns in the combustion chamber, resulting in the smoke being expelled through the exhaust. Excessive engine revolutions per minute (rpm) and excessive engine exhaust temperature may cause other issues in the engine but are not directly related to the smoke from the exhaust stack. Fuel mixing with the airflow is also unlikely to cause smoke, as it is a normal part of the combustion process.
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.
46.
Which could cause the butterfly valve to oscillate (continually open and close)?
Correct Answer
D. Pneumatic load thermostat.
Explanation
A pneumatic load thermostat can cause the butterfly valve to oscillate because it is designed to regulate the flow of air based on changes in temperature. If the thermostat detects a change in temperature, it will adjust the air pressure, which in turn affects the position of the butterfly valve. This constant adjustment of the valve can cause it to oscillate, continually opening and closing.
47.
Which three things are necessary to produce an electromotive force (EMF) mechanically?
Correct Answer
C. Magnetic field, a conductor, and relative motion.
Explanation
In order to produce an electromotive force (EMF) mechanically, three things are necessary: a magnetic field, a conductor, and relative motion. The presence of a magnetic field is required to induce the EMF in the conductor. The conductor acts as a medium for the flow of electrons, which creates the EMF. Finally, relative motion between the magnetic field and the conductor is needed to generate the EMF. This relative motion causes the magnetic field lines to cut across the conductor, resulting in the production of the 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 generator operates based on the principle of electromagnetic induction, where a changing magnetic field induces an electric current in a conductor. By increasing the strength of the magnetic field, more lines of force will cut across the conductor, resulting in a greater induced current and thus increasing the generator's 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 DC generator is able to produce an increased output. This is because the multiple coils increase the amount of wire and thus the amount of current that can be generated. Additionally, the generator will produce almost constant DC, as the coils on the shaft maintain a consistent direction of current flow. The increased output and constant DC make this option the correct answer.
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 slip rings and armature. The slip rings are used to transfer the generated electrical energy from the rotating armature to an external circuit. The armature, on the other hand, is the rotating component of the generator that contains the wire windings. These windings are responsible for generating the alternating current as they rotate within the magnetic field created by the stator windings. Therefore, the armature is the correct answer as it is an essential part of the rotor in an AC generator.