Description : What determines the phase relationship between the voltages in a two-phase ac generator?
Last Answer : Placement of armature coils.
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 : 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
Last Answer : Answer: C
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 : 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 : 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 two methods of connecting the outputs from a three-phase alternator to the load?
Last Answer : Wye and Delta.
Description : How many voltage outputs are available from a two-phase three-wire alternator?
Last Answer : Three.
Description : For the illustrated wiring of a three phase alternator, which statement is true about the current? EL-0074 A. phase current is 1.73 times the line current B. line current is 1.73 times the ... . there is no relationship between phase current and line current D. line current is equal to phase current
Last Answer : Answer: D
Description : What is the frequency of the output voltage of an alternator with four poles that is rotated at 3600 rpm?
Last Answer : 120 Hz.
Description : What two factors determine the frequency of the output voltage of an alternator?
Last Answer : Speed of rotation and number of poles.
Description : What is the part of an alternator in which the output voltage is generated?
Last Answer : Armature.
Description : The output voltage of a three-phase alternator is regulated by the _____________. A. AC voltage to the armature B. AC voltage to the field C. DC voltage to the armature D. DC voltage to the field
Description : The input and output signals of a JFET amplifier have what phase relationship?
Last Answer : They are 180 degrees out of phase.
Description : You are paralleling two alternators. The synchronizing lamps grow dim and are totally darkened as the synchroscope pointer approaches the 0° position. This indicates that the ____________. A. alternator ... be closed C. incoming alternator is running too slowly D. synchroscope is defective or broken
Last Answer : Answer: B
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 : 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 : There is a relationship between total current and current through the individual components in a circuit. What is this relationship in a series circuit and a parallel circuit?
Last Answer : The source voltage would have to be increased to 640 volts
Description : At high discharge rates, nickel-cadmium storage batteries are superior to lead-acid batteries because they __________. A. require fewer cells for the same voltage and less mounting space B. are able to ... times without much damage D. have no individual cells to replace at the end of useful life
Description : Which of the following statements is true concerning simple parallel resistance circuits? A. The total current flow equals the sum of the individual currents. B. The total current flow equals the ... resistance. D. The total voltage equals the sum of the individual voltages across each resistance.
Last Answer : Answer: A
Description : Which of the following statements concerning a simple parallel resistance circuit is correct? A. The voltage drop across each resistor is the same. B. The total current flow equals the reciprocal ... resistances. D. The total voltage equals the sum of the individual voltages across each resistance.
Description : The state of charge of a lead acid storage battery is best indicated by the _____________. A. testing of the individual cell voltages B. ampere hour capacity of the battery C. specific gravity of the electrolyte D. total cell voltages
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 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 : 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
Description : In a three-phase circuit, the phase voltages are _____________. A. 120°° apart B. 160°° apart C. 180°° apart D. 360°° apart
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 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 the basic transistor amplifier discussed earlier, what is the relationship between the polarity of the input and output signals?
Last Answer : The signals are opposite in polarity or 180 degrees out of phase with each other.
Description : What impedance relationship between the output of one circuit and the input of another circuit will provide the maximum power transfer?
Last Answer : Equal impedance.
Description : Nickel-cadmium batteries are superior to lead-acid batteries at high discharge rates because they _______________. A. deliver a large amount of power and can be recharged in a shorter time B. need ... less mounting space C. have higher output voltages and require no maintenance D. all of the above
Description : Basic operating characteristics of the operational amplifier such as gain and stability are the function of its _____________. A. differential input stage B. power output stage C. feedback circuit D. supply voltages
Description : What precaution should be taken with a vessel's impressed current cathodic protection system after a drydocking period during which the hull has been painted? A. Output currents should be carefully monitored ... slight (10-15%) overcurrent to the anodes should be allowed in order to speed drying.
Description : What type of prime mover requires a specially designed high-speed alternator?
Last Answer : Steam turbine.
Description : What is the main advantage of the rotating field alternator?
Last Answer : Output voltage is taken directly from the armature (not through brushes or slip rings).
Description : A three-phase alternator is operating at 450 volts, 250 amps at 0.6 power factor. If the power factor increases to 0.8, the kw load potential will increase by _____________. A. 38.525 kw B. 116.91 kw C. 155.88 kw D. 194.85 kw
Description : A three-phase alternator operates at 450 volts with a power factor of 0.8. If the ammeter indicates 250 amperes, what should be the KW meter reading? A. 90.00 KW B. 127.27 KW C. 155.70 KW D. 194.85 KW
Description : A three-phase alternator is developing 300 amps, with a 0.8 power factor, at 450 volts. The true indicated power on the kilowatt meter, located on the main switchboard, will be ____________. A. 133 kw B. 155 kw C. 187 kw D. 212 kw
Description : A three-phase alternator is operating at 450 volts with the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter would then read ____________. A. 181.4 KW B. 186.8 KW C. 194.2 KW D. 201.4 KW
Description : In the illustrated three phase alternator, line voltage is _________. EL-0074 A. 1.73 times the phase voltage B. equal to the phase voltage C. phase voltage divided by 1.73 D. unable to answer this question without knowing the line current
Description : When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the ______________. A. frequency of the incoming ... the bus D. terminal voltage of the incoming alternator is approaching that of the bus
Description : A three-phase alternator is operating at 450 volts with the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter reading would increase by ___ A. 17.8 KW B. 23.2 KW C. 30.6 KW D. 37.8 KW
Description : at the terminal of a three-phase 6.6Kv alternator a load R=200 ohm is connected between two-phase and the third phase is opened. Z1=z2=5 ohm Zo=2 find out the fault current .
Last Answer : 32A
Description : The phase sequence of a three-phase alternator will reverse if A) The field current is reversed keeping the direction of rotation same. B) The field current remains the same but the direction of ... The field current is reversed and also the direction of rotation is reversed D) None of the above
Last Answer : The phase sequence of a three-phase alternator will reverse if The field current remains the same but the direction of rotation is reversed
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.