Description : In a three-phase alternator, what is the phase relationship between the individual output voltages?
Last Answer : Each phase is displaced 120º from the other two
Description : What is the relationship between the transmitter and receiver stator voltages when their rotors are in correspondence?
Last Answer : The voltages are equal and oppose each other.
Description : What is the relationship of the voltage at C in figure 3-7 to the voltages at A and B?
Last Answer : C is 1.414 times greater than A or B.
Description : In a certain three -wire Y -connected generator, the phase voltages are 2 kV. The magnitudes of the line voltages will be: A. 2,000 V B. 6,000 V C. 666 V D. 3,464 V
Last Answer : In a certain three -wire Y -connected generator, the phase voltages are 2 kV. The magnitudes of the line voltages will be: 3,464 V
Description : In single-phase alternators, in order for the voltages induced in all the armature windings to add together for a single output, how must the windings be connected?
Last Answer : In series.
Description : AC and DC generators are similar in that they _____________. A. both generate alternating voltages B. both rectify the voltage before delivery C. are constructed at the same physical size for the same kilowatt rating D. both supply three-phase power
Last Answer : Answer: A
Description : What determines the frequency of AC produced in a generator?
Last Answer : The number of rotations of the coil in one second determines the frequency of a AC generator.
Description : What component causes a generator to produce dc voltage rather than ac voltage at its output terminals?
Last Answer : A commutator
Description : In a series-RLC circuit, what is the condition of the circuit if there is high impedance, low current, and low reactance voltages
Last Answer : Nonresonant (circuit is either above or below resonance)
Description : What three things prevent a CT rotor from turning when voltages are applied to its stator windings?
Last Answer : The rotor is specially wound, it is never connected to an ac supply, and its output is always applied to a high-impedance load.
Description : When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease (which one) in the resistance of the regulating device.
Last Answer : An increase.
Description : When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease in the resistance of the regulating device.
Last Answer : Increase.
Description : What are the most common insulators used for extremely high voltages?
Last Answer : Varnished cambric and oil-impregnated paper.
Description : If the load requirement consists of both positive and negative voltages, what technique is used in the voltage divider to supply the loads from a single voltage source?
Last Answer : The ground (reference point) is placed in the proper point in the voltage divider so that positive and negative voltages are supplied
Description : The development of excessive test voltages is avoided by the use of meggers equipped with what device?
Last Answer : Friction clutches.
Last Answer : Friction clutches
Description : A two-phase generator is connected to two 90Ω load resistors. Each coil generates 120 V ac. The value of current flowing through the common neutral line will be: A. 1.33 A B. 1.88 A C. 2.66 A D. 1.77 A
Last Answer : A two-phase generator is connected to two 90Ω load resistors. Each coil generates 120 V ac. The value of current flowing through the common neutral line will be: 1.77 A
Description : What will be the frequency of a three-phase, six pole, AC generator operating at 1800 revolutions per minute? A. 60 hertz B. 90 hertz C. 120 hertz D. 180 hertz
Last Answer : Answer: B
Description : Attempting to parallel an AC generator which is out of phase with the bus will result in which of the following problems? A. The breaker should trip. B. The KVA will decrease. C. The synchronizing lamps will burn out. D. The power factor will be unitized.
Description : An AC generator panel is fitted with both synchronizing lamps and a synchroscope. When the synchroscope pointer reaches the noon position, one synchronizing light is bright and the other is dark. This ... sequence is incorrect C. the phase sequence is correct D. the generator breaker may be closed
Description : The voltage of an operating AC turbogenerator is raised or lowered by adjusting the _____________. A. exciter generator governor controls B. synchronizing switch C. phase sequence switch D. generator field exciter
Last Answer : Answer: D
Description : Which of the following procedures should be used to determine the load of a threephase, delta wound, AC generator? A. Multiply the amperage in one phase by three. B. Divide the total amperage in all ... square root of three. D. Divide the total amperage in all phases by the square root of three.
Last Answer : Answer: C
Description : Regarding an AC generator connected to the main electrical bus; as the electric load and power factor vary, a corresponding change is reflected in the generator armature reaction. These changes in ... . governor speed droop setting B. voltage regulator C. balance coil D. phase-balance relay
Description : Ships’ generators produce 450-volt, three-phase, ac power; however, most equipment uses 117-volt, single-phase power What transformers and connections are used to convert 450- volt, threephase power to 117-volt, single-phase power?
Last Answer : A method of generating oscillations, a method of turning the oscillations on and off (keying), and an antenna to radiate the energy.
Description : To propagate energy down an arm of a hybrid ring duplexer, the two fields at the junction of the arm and the ring must have what phase relationship?
Last Answer : 180 degrees out of phase
Description : What will be the phase angle relationship of a six-pole, three-phase, rotating field generator? A. 60° B. 120° C. 180° D. 360°
Description : What is the fundamental difference between the phase relationship of the harmonics of the square wave as compared to the harmonics of a peaked wave?
Last Answer : All the odd harmonics are in phase with the fundamental in the square wave. This is not true of the odd harmonics in the peaked wave.
Description : The input and output signals of a JFET amplifier have what phase relationship?
Last Answer : They are 180 degrees out of phase.
Description : What is the phase relationship between the delayed and undelayed video?
Last Answer : Opposite.
Description : What signal is used to synchronize the coherent oscillator to a fixed phase relationship with the transmitted pulse?
Last Answer : Coho lock pulse.
Description : What type of target has a fixed phase relationship from one receiving period to the next?
Last Answer : Stationary.
Description : What is the phase relationship between current and voltage in an inductor?
Last Answer : Current lags voltage by 90° (ELI).
Description : When paralleling two alternators, the synchronizing lamps remain lit as the synchroscope pointer approaches the 0°. This indicates the _____________. A. incoming alternator is running too fast B. alternator ... apart C. synchroscope is defective or broken D. alternator power factors are in phase
Description : When paralleling two alternators the synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. This indicates the ____________. A. alternator voltages ... alternator is in phase with the bus voltage D. synchroscope pointer is defective or broken
Description : One important difference between wye-connected and delta-connected generators is that delta connections have ____________. A. line voltages equal to the vector sum of the phase voltages B. phase voltages 90° ... C. line current equal to the phase current D. line voltage equal to the phase voltage
Description : In a three-phase circuit, the phase voltages are _____________. A. 120°° apart B. 160°° apart C. 180°° apart D. 360°° apart
Description : In inverting amplifier, the phase difference between input and output voltages must be A. 30° B. 45° C. 90° D. 180°
Last Answer : 180°
Description : Ungrounded neutral transmission system is not recommended because of system (a) insulation being overstressed due to over voltages (b) insulation overstress may lead to failure and subsequent phase to phase faults (c) being inadequately protected against ground fault (d) all of the above
Last Answer : (d) all of the above
Description : The sending end and receiving end voltages of a three-phase transmission line are 10 kV/ph and 9.5 kV/ph, respectively. If the resistance drop is 150 V/ph and receiving end power factor is 0.8, the sending end power factor is (A) 0.745 lagging (B) 0.775 lagging (C) 0.8 lagging (D) 0.85 lagging
Last Answer : Vscos¢s-Vrcos¢r=IR
Description : In a dual-speed synchro system what determines the two specific speeds at which the data will be transmitted?
Last Answer : The gear ratio between the two transmitters.
Description : What determines the frequency, bandwidth, and power handling capability of a waveguide probe?
Last Answer : Size and shape
Description : A refracted wave occurs when a wave passes from one medium into another medium. What determines the angle of refraction?
Last Answer : The density of the two mediums, and the velocity of the waves.
Description : What determines whether these components are considered series or shunt?
Last Answer : . The relationship of the components to the output-signal path.
Description : Which quantity (voltage or current) determines the intensity of an electrical shock?
Last Answer : Current.
Description : What determines whether a differential synchro adds or subtracts?
Last Answer : The way the differential synchro is connected in a system is the deciding factor on whether the unit adds or subtracts its inputs.
Description : the voltage drop across RS and R1 determines the amount of base-emitter ____ for Q1.
Last Answer : Bias.
Description : What determines the rate of discharge of the capacitor in a filter circuit?
Last Answer : Value of capacitance and load resistance.
Description : What determines the chemical activity of an atom?
Last Answer : The number of electrons in the valence shell.
Description : What factor determines whether a radio wave is reflected or refracted by the ionosphere?
Last Answer : Thickness of ionized layer.
Description : In an externally synchronized radar, what determines the prr of the transmitter?
Last Answer : The master oscillator.