Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Marine Electrical Systems (Set 28)
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Question 1 of 30
Diesel generators #1 and #2 are operating in parallel at near full load capacity. Diesel generator #1 suddenly trips out mechanically due to low lube oil pressure. The reverse power relay functions properly and trips generator #1 electrically off the board. Which of the following actions should you carry out FIRST?
Browse Questions in Set 28
30 MCQs #1 Diesel generators #1 and #2 are operating in parallel at near full load capacity. Diesel generator #1 suddenly trips out mechanically due to low lube oil pressure. The reverse power relay functions properly and trips generator #1 electrically off the board. Which of the following actions should you carry out FIRST? #2 When shore power is being connected to a ship in dry dock, what must be ensured, assuming that the ship's generators are rated at 450 VAC, 60Hz with a total capacity of 5000 kW? #3 Upon failure of the normal power supply, by what means is the emergency generator placed on the line and connected to the emergency bus? #4 By what means is an AC generator prevented from becoming motorized? #5 As shown in the illustration of a DC machine which is configured as a generator, what is the polarity of the interpoles as compared to the main field poles? EL-0052 #6 What is the purpose of the commutator and brushes on a DC generator? #7 Why are armature cores in a DC generator made of laminated steel sheets? #8 How are the field windings of a DC shunt generator connected? #9 In referring to the illustration of the elementary DC generator, what statement is true? EL-0028 #10 In referring to the illustration of the Ward-Leonard drive system, what type of DC generator is used? EL-0153 #11 What two factors determine the magnitude of the generated voltage of a DC generator? #12 For the purposes of generating a DC voltage, which of the following factors is subject to vary for a particular generator installation while in operation? #13 What statement is true concerning the use of commutating poles (also known as interpoles) in DC generators? #14 What statement is true concerning the use of compensating windings in DC generators? #15 What is the purpose of the series field used in a stabilized shunt DC generator? #16 With what device is the simplest method of controlling the terminal voltage of compound-wound DC generator? #17 Prior to closing the circuit breaker when paralleling two DC generators, what must you be certain of? #18 Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel? #19 By what means is a DC generator prevented from becoming motorized if paralleling is accomplished without an equalizer? #20 How are fuses usually rated? #21 What is the characteristic that is associated with an "instantaneous-trip" single- element type fuse? #22 Due to the operating characteristics of the system, time lag fuses (or dual-element fuses) are necessary for use in what types of circuits? #23 Fuses are sometimes placed in series with a thermal trip-type circuit breaker. What is the purpose of a fuse used in this arrangement? #24 Which pair of safety disconnect switches shown in the illustration represents the exterior and interior views of a double throw switch? EL-0176 #25 What is the basic similarity between a circuit breaker and a fuse? #26 The arc resulting from the tripping of a circuit breaker is prevented from damaging the contacts. How is this done? #27 A thermal-magnetic circuit breaker for a 300 KW alternator is rated at 500 amperes at full continuous load. Which of the following conditions will trip the breaker? #28 As shown in the illustration, which of the following pieces of equipment is supplied with a circuit breaker providing both overload and short-circuit protection? EL-0165 #29 Which of the following pictures shown in the illustration is a control transformer, usually used to step down line voltage for supplying reduced voltage control circuits? EL-0177 #30 Relative to the number of turns of a secondary winding of a step-up transformer, what will be the number of turns of a primary winding?
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