2A672 Volume:1 Edit 6

An element is the simplest form of matter because it consists of only one type of atom. It cannot be broken down into simpler substances by chemical means. In contrast, a compound is made up of two or more different elements chemically combined, while a mixture is a combination of different substances that are not chemically bonded. Electrons are subatomic particles and not a form of matter on their own. Therefore, the correct answer is element.

When troubleshooting any electrical system, locating the last known source of power can help determine where to begin. By identifying the last point in the system where power was present, it becomes easier to trace the issue and identify potential causes of the problem. This starting point can provide valuable information about the flow of power and help narrow down the areas that need to be inspected or tested.

Valence electrons contain the most energy in an atom. Valence electrons are the outermost electrons in an atom's electron cloud and are involved in chemical reactions. These electrons are farther from the nucleus and experience less attraction, resulting in higher energy levels. The other options, such as orbiting electrons and K shell electrons, are not necessarily incorrect, but they do not specifically refer to the electrons with the most energy.

When the size of the plates or a capacitor is increased, the distance between the plates also increases. This results in an increase in the capacitance. Capacitance is directly proportional to the surface area of the plates and inversely proportional to the distance between them. Therefore, when the size of the plates or the capacitor is increased, the capacitance increases.

A diode is a semiconductor device that allows current to flow in one direction but blocks it in the opposite direction. This property is known as rectification and is the fundamental characteristic of a diode. It is commonly used in electronic circuits to control the flow of current and to convert AC to DC.

If there are eight electrons in the outermost shell of an atom, it is considered stable. This is because the octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable configuration with eight electrons in their outermost shell. Having a full outer shell of electrons makes the atom less likely to react with other atoms and more stable overall.

The factors that affect the resistance of a material are the area, temperature, and type of material. The area of the material affects the resistance because a larger area allows for more current to flow, resulting in lower resistance. The temperature of the material affects the resistance because as temperature increases, the resistance also increases. Lastly, the type of material affects the resistance because different materials have different resistivities, which determine their resistance.

Electromagnetic induction is the principle that explains the generation of voltage in a conductor when there is a relative motion between the conductor and a magnetic field. This phenomenon was discovered by Michael Faraday in the 19th century and is the basis for the functioning of generators and transformers. It is a fundamental principle in electromagnetism and plays a crucial role in various electrical and electronic devices.

The torsion shaft is specifically designed to break if the engine locks up. This is because the torsion shaft acts as a safety mechanism, absorbing the excessive torque and preventing damage to other components of the engine. By breaking, it releases the built-up energy and prevents further damage to the engine.

The correct answer explains that in an open circuit, there is no current flow, while in a shorted component, there is excessive current flow. This means that an open circuit acts as a break in the circuit, preventing the flow of current, while a shorted component creates a direct path for current to flow, resulting in an excessive amount of current.

If there is a loss of residual magnetism in the exciter field poles, the correct action to take is to field flash the generator. Field flashing involves temporarily applying a direct current to the exciter field windings to restore the residual magnetism. This process helps to build up the magnetic field in the generator and enables it to produce electricity. By field flashing the generator, the loss of residual magnetism can be rectified and the generator can start functioning properly again.

When a negative potential is connected to the cathode and a positive potential is connected to the anode of a PN junction, the diode is forward biased. In this configuration, the positive potential attracts the free electrons in the N-region towards the junction, while the negative potential attracts the holes in the P-region towards the junction. This creates a low resistance path for current to flow through the diode, allowing current to flow from the anode to the cathode. Therefore, the diode is forward biased in this scenario.

The major difference between an NPN transistor and a PNP transistor is the direction of current flow. In an NPN transistor, the current flows from the collector to the emitter, while in a PNP transistor, the current flows from the emitter to the collector. This difference in current flow direction is due to the arrangement and polarity of the transistor's layers and junctions.

The primary use of a silicon-controlled rectifier (SCR) is as an electronic switch. An SCR is a semiconductor device that can control the flow of electric current. It can be turned on or off using a small control signal, allowing it to act as a switch in various electronic circuits. This makes it useful for applications such as power control, motor control, and lighting control, where precise switching of electrical currents is required.

During operation of the AM32A-86D generator set, the control switch S13 should be placed in the "GENERATE" position to move the fuel rack and increase the engine speed to 2000 RPM. This position allows the generator to produce the necessary power output for generating electricity.

The voltage rheostat R61 is used to manually increase the output voltage of the A/M32A-86D generator set. A voltage rheostat is a variable resistor that can be adjusted to control the flow of current in a circuit, thereby changing the voltage. By adjusting the voltage rheostat R61, the user can manually increase the output voltage of the generator set to the desired level.

The correct answer is holding current. When a silicon-controlled rectifier (SCR) is turned on, it requires a certain amount of current, known as the holding current, to keep it conducting. If the current drops below this holding current, the SCR will turn off. The holding current is necessary to maintain the conduction state of the SCR and prevent it from turning off unintentionally.

The correct answer is Magnetic pick-up. A magnetic pick-up is a component of the B809 generator set speed control system that produces a frequency pulse train for engine speed reference. This pulse train is used by the system to regulate and control the speed of the engine.

The electrostatic field around a positive ion moves outward. This is because positive ions have a deficiency of electrons, resulting in a net positive charge. The positive charge attracts negatively charged particles, causing the electrostatic field to extend outward from the ion.

The probable cause of the excessively high exhaust gas temperature during operation of the A/M32-60A generator set is likely the pneumatic thermostat. The pneumatic thermostat is responsible for regulating the temperature of the exhaust gases, and if it is malfunctioning or not functioning properly, it can result in the temperature being too high. This can be a cause for concern as it can lead to overheating and potential damage to the generator set.

In an inductive circuit, current lags voltage by 90 degrees means that the current reaches its maximum value when the voltage is at its minimum value, and vice versa. This is because in an inductive circuit, the current takes time to build up due to the presence of inductance, causing it to lag behind the voltage. When the voltage is at its maximum value, the current has not yet reached its maximum and is still increasing. Similarly, when the current is at its maximum value, the voltage has already started to decrease.

The three leads in a unijunction transistor (UJT) are called emitter, base 1, and base 2.

When the B809 generator set alternation current (AC) card senses an AC supply fault, the AC contactor opens and the generator output stops. This means that the electrical connection between the generator and the load is interrupted, preventing the generator from supplying power. The opening of the AC contactor is a safety measure to protect the generator and the connected equipment from potential damage caused by the AC supply fault.

The best point to check voltage to the A/M32A-86D generator exciter field is at J8, terminal D-F.

Atoms having more than four electrons but less than eight electrons in their outermost energy level are known as insulators. Insulators are materials that do not conduct electricity easily because their outermost energy level is almost full, making it difficult for electrons to move freely. This lack of mobility of electrons prevents the flow of electric current through the material, thereby making it a poor conductor of electricity.

The basic principle of operation for transformers is mutual induction. Mutual induction refers to the process where a changing current in the primary coil of a transformer induces a voltage in the secondary coil. This is achieved through the magnetic field generated by the primary coil, which then links and induces a voltage in the secondary coil. Mutual induction allows for the transfer of electrical energy from one coil to another without direct electrical connection, making transformers an essential component in electrical power distribution systems.

The voltage regulator VR1 controls the strength of the A/M32A-86D generator exciter field L2. This means that VR1 is responsible for regulating the voltage output of the generator, which in turn determines the strength of the exciter field. By adjusting the voltage, VR1 ensures that the exciter field is at the desired level, which is crucial for the proper functioning of the generator.

The power rating of a circuit is equal to the product of the current flowing through it and the resistance. In this question, the power rating is given as 40 watts and the total current is 2 amps. By rearranging the formula, we can calculate the resistance by dividing the power rating by the current. Therefore, the resistance in the circuit is 40 watts divided by 2 amps, which equals 20 ohms.

In a series-parallel circuit, the total resistance (RT) is calculated by adding the resistances in the series portion and the reciprocal of the sum of the reciprocals of the resistances in the parallel portion. In this case, the series resistor R1 is 7 ohms, and the parallel resistors R2 and R3 are 8 ohms each. The sum of the series resistors is 7 ohms. The reciprocal of the sum of the reciprocals of the parallel resistors is 1/((1/8)+(1/8)) = 4 ohms. Adding the series and parallel portions, we get 7 ohms + 4 ohms = 11 ohms, which is the total resistance (RT) in the circuit.

In a series-parallel circuit, the total current (IT) is equal to the sum of the currents in the series and parallel branches. In this case, the series current (I1) is given as 9 amps and the parallel current (I2) is given as 5 amps. To find the total current, we add these two currents together: IT = I1 + I2 = 9 + 5 = 14 amps. Since the value of I3 is not listed, we cannot determine its value. Therefore, the correct answer is I3 = 4 amps and IT = 9 amps.

Analysis is considered the most difficult step in troubleshooting because it involves carefully examining and evaluating the data and information gathered during the recognition and verification, isolation and elimination, and repair and check steps. It requires a deep understanding of the problem, the ability to identify patterns or trends, and the skill to determine the root cause of the issue. Analysis often involves complex problem-solving techniques and may require additional research or expertise to reach a resolution.

The correct answer is (T1) and rectifier (CR26). This is because the exciter field voltage is supplied by the transformer (T1) and rectifier (CR26) combination. The transformer steps up or steps down the input voltage to the desired level, and the rectifier converts the alternating current (AC) output of the transformer into direct current (DC) to supply the exciter field voltage.

The correct answer is depletion region. In a semiconductor, the depletion region refers to the area where the P-type material and N-type materials are joined. This region is created due to the diffusion of charge carriers and the formation of a depletion layer, which results in a lack of free charge carriers. The depletion region plays a crucial role in the operation of semiconductor devices such as diodes and transistors.

Voltage is the correct answer because it represents the force or electric potential difference that drives the movement of free electrons through a conductor. It is the measure of the energy per unit charge required to move the electrons, and it determines the rate of flow of electric current. The greater the voltage, the stronger the force pushing the electrons, and the higher the current.

In a unijunction transistor (UJT), the emitter always points towards the base 1 lead. This is because the base 1 lead is connected to the emitter region of the UJT. The emitter is responsible for emitting the majority charge carriers (electrons or holes) into the base region, which then controls the conductivity of the UJT. By pointing the emitter towards the base 1 lead, the UJT is able to properly function and regulate its conductivity.

The injection pump is responsible for distributing and delivering an accurate amount of fuel to the engine cylinders in a B809 generator set fuel system. It ensures that the correct amount of fuel is injected into each cylinder at the right time, allowing for efficient combustion and optimal engine performance. The injection pump plays a crucial role in maintaining the fuel system's functionality and ensuring that the engine receives the necessary fuel supply.

The direct current (DC) card on the B809 generator set senses the condition of overtemperature. This means that the DC card is designed to detect and monitor the temperature of the generator set. If the temperature exceeds a certain threshold, the DC card will trigger an alarm or shut down the generator to prevent damage from excessive heat. This is an important safety feature to protect the generator set and ensure its proper functioning.

The probable cause for the undervoltage light coming on when placing S13 in the build-up position while operating an A/M32A-86D at governor speed is the memory time delay relay. This relay is responsible for providing a delay in the operation of certain components, and if it is malfunctioning or not functioning at all, it can cause the undervoltage light to come on.

The rate control section of the A/M32A-60 gas turbine engine load control valve controls the opening time. This means that the rate control mechanism determines how quickly or slowly the valve opens, allowing for precise control over the amount of gas flowing through the turbine engine. This section is responsible for regulating the rate at which the valve opens, ensuring optimal performance and efficiency of the engine. The diaphragm, load control, and mechanical linkage sections may play other roles in the valve's operation, but they do not specifically control the opening time.

A capacitor opposes any change in voltage in AC circuits because it can store and release electrical energy in response to alternating current. As the AC voltage changes direction, the capacitor charges and discharges, creating a phase shift between the voltage and current. This opposition to voltage change is due to the ability of the capacitor to store charge and resist sudden changes in voltage. In DC circuits, the capacitor charges to a steady voltage and does not oppose any change in voltage, making it ineffective in this case. Therefore, the correct answer is AC.

Switch S15 to the L-N position. This is the correct answer because if the AC voltmeter is reading 200 volts AC on all three phases, it indicates that the voltmeter is currently measuring the voltage between two phases (L-L) instead of between a phase and neutral (L-N). By switching S15 to the L-N position, the voltmeter will now measure the correct voltage between a phase and neutral. Adjusting VR1 or R61 would not be necessary in this situation as the issue is with the position of the switch.

During the first cycle of alternating current (AC) in a circuit using a bridge rectifier, two diodes are forward biased. The bridge rectifier consists of four diodes arranged in a bridge configuration. During the positive half-cycle of the AC, two diodes become forward biased and conduct, allowing the current to flow through them. The other two diodes become reverse biased and do not conduct. This arrangement ensures that the AC input is converted into a pulsating DC output.

The emitter is the most positive point in a PNP bipolar transistor because it is connected to the positive terminal of the power supply. This allows current to flow from the emitter to the base and collector, enabling the transistor to amplify signals and control the flow of current in the circuit. The emitter is responsible for emitting the majority charge carriers (electrons or holes) into the base region, which then controls the transistor's behavior.

The secondary winding of a transformer acts as a conductor and provides the path into which the voltage is induced. When an alternating current is applied to the primary winding, it creates a changing magnetic field which induces a voltage in the secondary winding. This voltage can then be used to power electrical devices or be further transformed to different voltage levels. The secondary winding is typically connected to the load and is responsible for delivering the desired output voltage.

The correct answer is AUTOMATIC because in order to test the loas contactor relay K1, the automatic-manual voltage control must be placed in the automatic position. This is because the automatic position allows the voltage control to operate automatically, which is necessary for testing the relay. Placing it in any other position would not allow for proper testing of the relay.

Apparent power is the combination of real power and reactive power in an AC circuit. It is measured in kilo-volt-amperes (KVA) because it represents the total power consumed by the circuit, taking into account both the voltage and current. Kilowatts (KW) and kilo-volt-amperes (KVA) are similar, but KVA includes the reactive power component, which is important in determining the overall power requirements and sizing of electrical equipment. Kilo-watts-amperes (KWA) is not a standard unit of measurement and is not commonly used in electrical engineering.

A zener diode is connected in parallel to the load in a circuit to regulate voltage. When connected in this way, the zener diode acts as a voltage regulator by maintaining a constant voltage across the load. It does this by conducting current in the reverse direction once the voltage across it exceeds its breakdown voltage. This ensures that the voltage across the load remains constant, even if the input voltage fluctuates. Connecting the zener diode in parallel to the load allows it to shunt excess current and maintain a stable voltage output.

If the arrow in a bipolar transistor is pointing away from the base, it indicates that the transistor is an NPN type. In an NPN transistor, the majority charge carriers are electrons, and the arrow represents the direction of the conventional current flow. The base region is P-type, while the emitter and collector regions are N-type. The arrow pointing away from the base signifies the flow of electrons from the emitter to the collector, which is characteristic of an NPN transistor.

The operating voltage of the blower motor control relay on the A/M24T-8 load bank is 28 VDC.

In a P-type material, majority carriers are holes, which are created due to the presence of acceptor impurities. Minority carriers, on the other hand, are the carriers that are present in lower concentrations compared to the majority carriers. In a P-type material, the minority carriers are electrons. These electrons are thermally generated and are present in small numbers due to the low concentration of donor impurities in the material. Therefore, the correct answer is electrons.