Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Marine Electrical Systems (Set 7)
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Question 1 of 30
If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller control circuit illustrated in figure A of the illustration? Illustration EL-0011
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30 MCQs #1 If the supply voltage is 220 volts 60 Hz, what is the operating voltage of the motor controller control circuit illustrated in figure A of the illustration? Illustration EL-0011 #2 A battery is connected to a circuit containing three resistors in parallel. The values of the three resistors are 2 ohms, 3 ohms, and 6 ohms. What is the voltage of the battery if the total circuit current is 12 amps? #3 In the illustration, 1, 2, 3 and 4 are 12 volt batteries. What will be the nominal voltage as read by a voltmeter across the output of the battery bank? Illustration EL-0107 #4 What is the power consumed by 'R2' in the circuit illustrated in figure "B", if the applied voltage is 24 volts and the resistance of R1 is 3 ohms, R2 is 4 ohms, and R3 is 5 ohms, respectively? Illustration EL-0020 #5 How is the power dissipated as heat in a direct current circuit calculated? #6 What is the wattage of a heating element drawing a current of 30 amperes, at 120 volts? #7 A 125 volt DC motor is rated at 10 kW. What is the current rating of the motor? #8 Two 100 watt light bulbs rated at 100 volts are connected in parallel across a 100 volt power supply. What will be the total power consumed by the two bulbs? #9 What power would be consumed by the series resistor in the circuit shown in the illustration if the source is 30 volts, the resistance for R1 is 10 ohms, R2 is 10 ohms and R3 is 10 ohms? Illustration EL-0032 #10 How many watts of power is equal to one horsepower? #11 A three-phase alternator operates at 450 volts with a 0.8 power factor. If the ammeter indicates 250 amperes, what should be the kW meter reading? #12 What will be the frequency of a three-phase, 16 pole, AC generator operating at 3000 revolutions per minute? #13 What is the rotor speed of a six pole, 60 cycle, induction motor operating at full load with 3% slip? #14 A four pole turbo generator is used in conjunction with a 160 pole propulsion motor. If the generator is turning at 3,200 RPM, what is the current speed of the propeller? #15 An AC generator produces 60 Hz at 1800 RPM. If the generator speed is increased to 1830 RPM, what will happen to the frequency in Hz? #16 In a 60 Hz AC system, what is the duration in seconds for one complete cycle? #17 The turns ratio of the step down transformer with dual voltage secondary as shown in figure "B" of the illustration is two to one (total). If 440 volts were applied to terminals 'H1' and 'H2', what would be measured across 'X1-X3' and 'X2-X4' assuming that the secondary windings are connected in parallel? Illustration EL-0082 #18 What is the maximum allowable primary current of a 2 kVA step-down transformer with a four to one turns ratio if the primary is connected across a 440 volt line? #19 In figure "2" of the diagram shown in the illustration, the three phase power transformer has a step-down turns ratio of four to one. If a three-phase 440 volt supply is connected to terminals 'A1-B1-C'1, what voltage should develop across terminals 'A2-B2-C2'? Illustration EL-0084 #20 A load is connected across the secondary of the step up transformer shown in figure "B" of the illustration and the current drawn by the load is 10 amps. If the turns ratio is 1 to 10 and the input voltage is 110 VAC, what will be the current drawn by the primary? Illustration EL-0055 #21 What should be the primary consideration when choosing a battery for a particular application? #22 The individual 6 volt lead-acid batteries, when connected as shown in the illustration, as a battery bank would produce how many volts? Illustration EL-0070 #23 The wet-cell storage batteries shown in the illustration are connected in what configuration? Illustration EL-0070 #24 The nominal open-circuit voltage of one cell of a fully charged lead-acid battery is approximately how many volts? #25 How many cells are within in a 24 volt lead-acid battery? #26 In the illustrated views of a lead acid battery as shown in figures "A" and "B", what battery component has the sole function of preventing the individual plates in the negative plate group from coming into direct contact with the individual plates in the positive plate group? Illustration EL-0031 #27 The electrolyte used in a nickel-cadmium battery is distilled water and what other substance? #28 In general, why are nickel-cadmium storage batteries superior to lead-acid batteries? #29 What is the approximate voltage per cell produced by the nickel-iron (Edison) battery? #30 What is a hydrometer used to measure?
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