1.
(401) 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 electromagnetic principles to generate a rotating motion, which can be used to power various machines and equipment. Unlike a generator, which converts mechanical energy into electrical energy, a motor performs the opposite function. A converter is a broad term that can refer to various devices used to convert one form of energy into another, but it is not specifically designed to convert electrical energy into mechanical energy. An inverter, on the other hand, is used to convert direct current (DC) into alternating current (AC), and it does not directly convert electrical energy into mechanical energy. Therefore, the correct answer is motor.
2.
(401) When a motor continues turning after reaching its limit, this is known as
Correct Answer
A. Inertia.
Explanation
When a motor continues turning after reaching its limit, it is due to inertia. Inertia is the tendency of an object to resist changes in its state of motion. In this case, the motor's inertia causes it to keep turning even after it has reached its limit, as it takes time for the motor to slow down and come to a stop.
3.
(402) 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 dependent on both the force applied and the distance from the axis of rotation. It is commonly used in physics and engineering to describe the turning or twisting force applied to an object. Wattage and horsepower are units used to measure power, while opposition to applied voltage refers to resistance.
4.
(403) In order to operate, a single-phase induction motor requires
Correct Answer
D. A starting system.
Explanation
A single-phase induction motor requires a starting system in order to operate. Unlike a three-phase induction motor, a single-phase induction motor does not have a rotating magnetic field to start the motor by itself. Instead, it requires an external starting system such as a capacitor start or a split-phase start mechanism to provide the necessary starting torque. The starting system helps to create a rotating magnetic field and initiates the motor's rotation, allowing it to operate efficiently. Therefore, a starting system is essential for the operation of a single-phase induction motor.
5.
(403) The difference in the rotor’s speed of rotation and the stator magnetic field is known as
Correct Answer
C. Slip.
Explanation
The difference in the rotor's speed of rotation and the stator magnetic field is known as slip. Slip is an important concept in electrical machines, particularly in induction motors. It represents the relative speed between the rotating magnetic field produced by the stator and the rotor. Slip is necessary for the production of torque in the motor, as it creates a rotating magnetic field that induces currents in the rotor, resulting in the generation of torque. Therefore, slip is the correct answer as it accurately describes the difference in speed between the rotor and the stator magnetic field.
6.
(403) Which induction motor has the highest starting torque?
Correct Answer
A. Capacitive start.
Explanation
Capacitive start induction motors have the highest starting torque compared to squirrel cage, shaded pole, and split phase induction motors. This is because the capacitive start motor uses a capacitor in series with the starting winding, which creates a phase shift between the main and starting windings. This phase shift produces a rotating magnetic field, resulting in a higher starting torque. Squirrel cage, shaded pole, and split phase induction motors have lower starting torques compared to capacitive start motors.
7.
(404) The three-phase induction motor does not require
Correct Answer
A. Slip.
Explanation
The three-phase induction motor requires slip in order to generate torque. Slip is the difference between the synchronous speed of the rotating magnetic field and the actual speed of the rotor. This difference creates the necessary relative motion between the stator and rotor, allowing the motor to produce torque. Without slip, the motor would not be able to start or operate. Therefore, slip is necessary for the functioning of a three-phase induction motor.
8.
(405) 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 operates on the principle of magnetic fields rotating at a synchronous speed. The stator windings are responsible for creating the rotating magnetic field, and in order to achieve a smooth and efficient rotation, the windings need to be evenly spaced around the stator. A spacing of 120 degrees ensures that the magnetic field produced by each winding is evenly distributed and allows for optimal performance of the motor.
9.
(406) During an inspection of a direct current (DC) motor, check the brushes for
Correct Answer
B. Seating.
Explanation
During an inspection of a 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. If the brushes are not seated correctly, it can result in poor electrical contact, leading to reduced motor performance and efficiency. Therefore, checking the brushes for seating ensures that they are properly aligned and making good contact with the commutator, which is crucial for the motor's optimal functioning.
10.
(407) The first thing you should do when troubleshooting a motor is perform a
Correct Answer
C. Visual inspection.
Explanation
When troubleshooting a motor, the first thing you should do is perform a visual inspection. This involves visually inspecting the motor for any obvious signs of damage, such as loose connections, burnt wires, or broken parts. By conducting a visual inspection, you can identify any visible issues that may be causing the problem with the motor. This step is important because it allows you to quickly identify and address any visible problems before moving on to more complex diagnostic tests.
11.
(408) In component removal, if wires are to be soldered, do not
Correct Answer
D. Cut them unless there is sufficient length remaining for resoldering.
Explanation
When performing component removal, it is advised not to resolder the wires until they have been bench checked. Instead, the recommended approach is to cut the wires unless there is enough length left for resoldering. This ensures that the wiring is intact and can be properly replaced if needed.
12.
(408) Perform an operational check of the unit
Correct Answer
C. Before final reassembly of the enclosure.
Explanation
Performing an operational check of the unit before final reassembly of the enclosure ensures that the unit is functioning properly and all components are working as expected. This step allows any issues or defects to be identified and addressed before the final reassembly, reducing the risk of having to disassemble the enclosure again if a problem is discovered later. It also ensures that the unit is fully tested and ready for use once it is reassembled.
13.
(409) What controls the amount of fuel injected when constant-stroke fuel injection pumps are used?
Correct Answer
B. Control rack.
Explanation
When constant-stroke fuel injection pumps are used, the amount of fuel injected is controlled by the control rack. The control rack is responsible for determining the position of the fuel rack in the pump, which in turn regulates the amount of fuel that is injected into the engine cylinders. By adjusting the position of the control rack, the fuel delivery can be increased or decreased, allowing for precise control of the fuel injection process.
14.
(409) The constant-stroke pump plunger determines the amount of fuel delivered by the position of a
Correct Answer
C. Helical groove.
Explanation
The correct answer is helical groove. In a constant-stroke pump, the fuel is delivered by the position of a helical groove. The helical groove is a spiral-shaped channel on the plunger that controls the flow of fuel. As the plunger moves up and down, the helical groove allows fuel to enter and exit the pumping chamber, determining the amount of fuel delivered. This design ensures a consistent and controlled flow of fuel to the engine.
15.
(409) What provides the pressure to operate a pressure injector?
Correct Answer
A. Fuel from the fuel system.
Explanation
The pressure to operate a pressure injector is provided by fuel from the fuel system. Pressure injectors are used in engines to deliver fuel into the combustion chamber at high pressure for efficient combustion. Fuel is pressurized by a fuel pump and then injected into the engine cylinders through the pressure injector. This ensures that the fuel is atomized and dispersed evenly, allowing for optimal fuel-air mixture and combustion efficiency.
16.
(409) 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 device or machine. It ensures that the speed does not exceed a certain limit, preventing any potential damage or hazards. Therefore, the correct answer is maximum speed.
17.
(410) What is also reduced when a lubricant reduces friction?
Correct Answer
A. Dirt and metal particles.
Explanation
When a lubricant reduces friction, it also reduces the presence of dirt and metal particles. This is because the lubricant forms a protective layer between moving parts, preventing them from coming into direct contact and causing wear. As a result, the friction is reduced, and any dirt or metal particles that may have been present are less likely to be dislodged or generated during the movement of the parts.
18.
(410) Which function of a lubricant compensates for microscopic irregularities in the cylinder wall?
Correct Answer
B. Sealing.
Explanation
The function of a lubricant that compensates for microscopic irregularities in the cylinder wall is sealing. When a lubricant is applied to the cylinder wall, it forms a thin film that fills in the tiny gaps and imperfections on the surface. This helps to create a smooth and even surface, reducing the chances of leakage and improving the overall sealing of the cylinder.
19.
(411) 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 transfer heat from the coolant to the surrounding air, allowing the coolant to cool down before it is circulated back into the engine. The radiator consists of a series of tubes and fins that increase the surface area for better heat dissipation. As coolant flows through the tubes, it releases heat to the fins, and the air passing over the fins carries away the heat, cooling the coolant in the process.
20.
(411) Which liquid cooling system component maintains positive pressure within the cooling system, causes the boiling point of the coolant to be higher, and permits the engine to operate at higher temperature without the coolant boiling?
Correct Answer
C. Radiator cap.
Explanation
The radiator cap is the component that maintains positive pressure within the cooling system. This pressure raises the boiling point of the coolant, allowing the engine to operate at higher temperatures without the coolant boiling.
21.
(411) The purpose of the cooling system thermostat is to maintain correct engine
Correct Answer
B. Coolant temperature.
Explanation
The cooling system thermostat is responsible for regulating the coolant temperature in the engine. It does this by controlling the flow of coolant through the radiator. When the engine is cold, the thermostat remains closed, preventing coolant from flowing through the radiator and allowing the engine to warm up quickly. Once the engine reaches the optimal operating temperature, the thermostat opens, allowing coolant to circulate and maintain a consistent temperature. Therefore, the purpose of the cooling system thermostat is to maintain the correct coolant temperature in the engine.
22.
(412) 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 must be changed so that the intake and exhaust valves are open at the same time. This allows for better air flow and combustion efficiency, resulting in increased power and performance. By opening both valves simultaneously, the engine can take in more air and expel exhaust gases more effectively, leading to improved overall engine performance.
23.
(412) The advantage of using a turbocharger on a diesel engine is the fuel consumption is
Correct Answer
C. Used more efficiently and horsepower is increased.
Explanation
A turbocharger on a diesel engine increases the efficiency of fuel usage by compressing the air intake, allowing more air to enter the engine. This results in better mixing of the fuel with the air charge, leading to more efficient combustion and increased horsepower. Therefore, the fuel is used more efficiently and the horsepower is increased.
24.
(413) The maintenance procedure that is considered to be the cheapest and most effective means of reducing injection equipment problems and maintenance costs is
Correct Answer
D. Preventive maintenance.
Explanation
Preventive maintenance is the most cost-effective procedure for reducing injection equipment problems and maintenance costs. It involves regularly inspecting and servicing equipment to prevent breakdowns and identify potential issues before they become major problems. By conducting routine maintenance, such as cleaning, lubricating, and replacing worn parts, the chances of equipment failure are significantly reduced. This proactive approach helps extend the lifespan of the equipment, improves its performance, and minimizes the need for costly repairs or component replacements.
25.
(413) 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 protect the system from abrasion caused by foreign particles. These particles can enter the fuel system and cause damage to the engine components if not filtered out. By removing these particles, the filtration step ensures that the fuel flowing through the system is clean and free from any abrasive contaminants that could potentially cause blockage or damage. This helps to maintain the efficiency and longevity of the fuel system and prevents any potential malfunctions or failures.
26.
(414) The first thing you should do when operating a diesel engine is to
Correct Answer
C. Perform a preoperational check.
Explanation
When operating a diesel engine, it is important to perform a preoperational check. This involves checking various components of the engine to ensure they are in proper working condition before starting the engine. This helps to identify any potential issues or malfunctions that could affect the engine's performance or safety. Retorquing the engine-mount bolts, draining moisture from the fuel system, and performing a periodic inspection are also important maintenance tasks for a diesel engine, but they are not the first thing that should be done when operating the engine.
27.
(415) To locate a misfiring cylinder in the diesel engine, use a screw driver to
Correct Answer
B. Hold the injector follower down or closed.
Explanation
To locate a misfiring cylinder in a diesel engine, holding the injector follower down or closed with a screwdriver is recommended. This is because by doing so, the fuel supply to the cylinder is cut off, which helps in identifying the misfiring cylinder. When the injector follower is held down or closed, the fuel flow is interrupted, causing a noticeable change in the engine's sound or performance. This method allows for isolating the specific cylinder that is causing the misfire, making it easier to diagnose and fix the issue.
28.
(416) The component that reduces the turbine engine speed for accessories is the
Correct Answer
A. Gear case.
Explanation
The gear case is the component that reduces the turbine engine speed for accessories. It is responsible for transmitting power from the engine to various accessories, such as the generator, hydraulic pump, and air conditioning compressor. By using gears, the gear case can decrease the high rotational speed of the engine to a suitable speed for these accessories to operate efficiently. The starter motor is used to start the engine, the tachometer generator measures the engine speed, and the multiple centrifugal switch assembly is used in electric motors to control their operation.
29.
(416) During starting, the turbine engine is rotated up to 20 percent by the
Correct Answer
D. Starter motor.
Explanation
During starting, the turbine engine needs to be rotated in order to initiate the combustion process. The rotating motion is provided by the starter motor, which is specifically designed for this purpose. The AC generator, fuel pump and control unit, and tachometer generator are not responsible for rotating the turbine engine during starting.
30.
(416) 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 will cause the tachometer generator to become inoperative. The tachometer generator is connected to the drive shaft and relies on its rotation to generate an electrical signal that is used to measure the engine's speed. Therefore, if the drive shaft is sheared and no longer rotates, the tachometer generator will not be able to generate the necessary signal, rendering it inoperative.
31.
(417) During gas turbine engine operation, the air is accelerated by the
Correct Answer
A. Diffusers.
Explanation
During gas turbine engine operation, the air needs to be accelerated to increase its velocity before entering the combustion chamber. This is achieved by using diffusers, which are a type of component that slows down the airflow while increasing its pressure. Diffusers are designed to convert the kinetic energy of the fast-moving air into pressure energy, allowing for efficient combustion and overall engine performance.
32.
(417) The component of the gas turbine engine that causes the air velocity to be reduced, resulting in an increase in pressure, is the
Correct Answer
D. Divergent diffuser.
Explanation
The correct answer is divergent diffuser. A divergent diffuser is a component of a gas turbine engine that is responsible for reducing the air velocity and increasing the pressure. It is designed to expand the flow area of the air, allowing it to slow down and convert its kinetic energy into pressure energy. This helps to improve the efficiency and performance of the engine by ensuring that the air is at the appropriate pressure for combustion and subsequent power generation.
33.
(417) 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 component of the engine where combustion takes place. It is designed to provide a controlled environment for the fuel and air mixture to burn efficiently and generate the necessary energy to drive the turbine. The combustor can is typically located between the compressor and the turbine sections of the engine.
34.
(418) 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 supplying pressurized fuel to the combustion chamber. The boost pump helps to ensure a consistent flow of fuel to the main fuel pump, ensuring proper fuel delivery to the combustion chamber for efficient combustion.
35.
(418) The two pressure controls in the fuel pump and control unit of the turbine engine are the
Correct Answer
B. Acceleration limiter valve and governor.
Explanation
The two pressure controls in the fuel pump and control unit of the turbine engine are the acceleration limiter valve and governor. These controls work together to regulate the fuel pressure and ensure that it is maintained within safe limits. The acceleration limiter valve limits the rate at which the fuel pressure can increase, preventing sudden surges that could damage the engine. The governor, on the other hand, adjusts the fuel flow to maintain a constant speed and prevent overspeeding. Together, these controls help to maintain the proper fuel pressure and ensure the safe and efficient operation of the turbine engine.
36.
(418) Crack pressure is defined as the amount of
Correct Answer
C. Fuel pressure that is required to overcome spring tension.
Explanation
Crack pressure is the amount of pressure required to overcome the force of a spring and allow a fluid or gas to flow through a valve or opening. In this case, the crack pressure is specifically referring to the fuel pressure that is needed to overcome the tension of a spring in order for fuel to flow.
37.
(418) Which turbine engine fuel system component is normally closed and is energized open when the engine builds up sufficient oil?
Correct Answer
D. Fuel shutoff solenoid valve.
Explanation
The fuel shutoff solenoid valve is normally closed and is energized open when the engine builds up sufficient oil. This valve is responsible for controlling the flow of fuel to the engine. When the engine has enough oil pressure, the solenoid valve opens, allowing fuel to flow into the engine. This ensures that the engine only receives fuel when it is ready to start and prevents any potential damage that could occur if fuel were to enter the engine without sufficient oil pressure. The other options, such as the governor, oil shutoff valve, and boost pump valve, are not directly related to controlling the flow of fuel in the same way as the fuel shutoff solenoid valve.
38.
(418) What types of inputs are used to control the fuel solenoid for the delivery of fuel to the atomizer within the turbine engine fuel system?
Correct Answer
A. Oil pressure and electrical.
Explanation
Oil pressure and electrical inputs are used to control the fuel solenoid for the delivery of fuel to the atomizer within the turbine engine fuel system. Oil pressure is necessary to ensure that the solenoid is activated and allows fuel to flow to the atomizer. Electrical inputs are used to control the opening and closing of the solenoid, regulating the fuel flow. Therefore, both oil pressure and electrical inputs are essential for the proper functioning of the fuel solenoid in delivering fuel to the atomizer.
39.
(418) The turbine engine component that prevents fuel from accumulating in the plenum is the
Correct Answer
B. Drain valve.
Explanation
The drain valve is the turbine engine component that prevents fuel from accumulating in the plenum. The plenum is a chamber where fuel is stored before being injected into the combustion chamber. If fuel were to accumulate in the plenum, it could result in a dangerous buildup of fuel that could potentially cause an explosion. The drain valve is responsible for removing any excess fuel or condensation that may collect in the plenum, ensuring safe and efficient operation of the turbine engine.
40.
(419) Lubrication system pressure in the turbine engine is regulated through a
Correct Answer
C. Pressure relief valve.
Explanation
The correct answer is pressure relief valve. In a turbine engine, the lubrication system pressure needs to be regulated to ensure proper lubrication of the engine components. The pressure relief valve is responsible for maintaining the desired pressure by diverting excess oil flow back to the oil tank when the pressure exceeds the set limit. This helps to prevent damage to the engine due to excessive pressure and ensures that the lubrication system operates effectively. A flow check valve, filter bypass valve, and temperature regulator are not directly involved in regulating the lubrication system pressure.
41.
(419) 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) when there is insufficient oil pressure. This switch is designed to monitor the oil pressure and if it falls below a certain threshold, it sends a signal to shut down the GTC. By doing so, it helps to protect the GTC from damage that could occur due to inadequate lubrication. The oil pressure solenoid, oil drain switch, and ignition coil are not directly related to preventing GTC operation with insufficient oil pressure.
42.
(420) The load section of the load control valve consists of chambers
Correct Answer
A. 1 and 2.
Explanation
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 other options, 1 and 4, 2 and 3, and 3 and 4, are not correct because they do not accurately describe the load section of the valve.
43.
(420) The time required to open the load control valve on the turbine engine is controlled by the
Correct Answer
C. Rate adjustment screw.
Explanation
The correct answer is the rate adjustment screw. The time required to open the load control valve on the turbine engine is controlled by the rate adjustment screw. This screw is responsible for adjusting the rate at which the valve opens, allowing for precise control of the flow of fuel or air into the engine. By adjusting the rate, the engine can be optimized for different operating conditions, ensuring efficient and reliable performance. The mechanical linkage, actuator diaphragm, and actuator return spring may play a role in the overall operation of the load control valve, but they do not directly control the time required to open it.
44.
(420) 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. This screw controls the rate at which the valve opens and closes, so if it is not properly adjusted, it can result in the valve opening too slowly or too quickly. This can lead to inefficiencies in the turbine's operation and affect its performance.
45.
(420) In the turbine engine, what prevents rupture of the rate diaphragm?
Correct Answer
A. Adjustment screw.
Explanation
The adjustment screw prevents rupture of the rate diaphragm in a turbine engine. It allows for the adjustment of the rate diaphragm, which controls the flow of fuel into the engine. By adjusting the screw, the operator can regulate the fuel flow and prevent excessive pressure that could lead to rupture of the diaphragm.
46.
(421) 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 or particles, can obstruct the airflow and cause damage to the engine. Checking for leakage, excess heat, and hairline cracks are also important aspects of the inspection, but in this case, the focus is specifically on identifying and removing any foreign objects that may be present in the intake and exhaust areas.
47.
(422) Normal acceleration characteristics of the gas turbine compressor (GTC) include
Correct Answer
B. A decrease in vibration after 35 percent.
Explanation
The normal acceleration characteristics of a gas turbine compressor (GTC) include a decrease in vibration after 35 percent. This means that as the GTC accelerates, the vibration levels initially increase but then start to decrease after it reaches 35 percent of its acceleration. This decrease in vibration is considered normal and indicates that the GTC is operating smoothly and without any issues.
48.
(423) Common or frequently occurring troubles in a unit, their cause, and remedies may be found in the
Correct Answer
C. Troubleshooting chart.
Explanation
A troubleshooting chart is a tool that provides a systematic approach to identify and resolve common or frequently occurring troubles in a unit. It contains a list of potential problems, their causes, and recommended remedies. By referring to the troubleshooting chart, technicians can quickly diagnose and fix issues, saving time and effort. The historical record and maintenance record may contain information about past problems and their solutions, but they may not provide a structured and organized approach like a troubleshooting chart does. The illustrated parts breakdown, on the other hand, is a visual representation of the unit's components and may not include troubleshooting information.
49.
(424) If no oil pressure is available from the main oil pump assembly on the gas turbine compressor (GTC), what should you replace?
Correct Answer
B. Entire assembly.
Explanation
If no oil pressure is available from the main oil pump assembly on the gas turbine compressor (GTC), the entire assembly should be replaced. This is because if there is no oil pressure, it indicates a malfunction or failure in the entire assembly, and replacing just one component like the pump or valve may not solve the issue. Replacing the entire assembly ensures that all the components are new and functioning properly, restoring the oil pressure to the required level for the GTC.
50.
(424) 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 and creates smoke when it comes into contact with the hot components of the engine. Excessive engine revolutions per minute (rpm) do not directly cause smoke from the exhaust stack. Similarly, excessive engine exhaust temperature and fuel mixing with the airflow may cause other issues, but they are not specifically related to the smoke pouring from the exhaust stack.