Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR

USCG Marine Electrical Systems (Set 17)

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Question 1 of 30

Which of the listed items will stop a motor due to a reduction in voltage and automatically restart it when the voltage is restored to normal?

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30 MCQs

#1 Which of the listed items will stop a motor due to a reduction in voltage and automatically restart it when the voltage is restored to normal? #2 In the illustrated motor controller, what do the contacts across terminals "3" and "4" of the control circuit represent? Illustration EL-0017 #3 As shown in the illustration, which of the following conditions will occur as a result of a momentary loss of power? Illustration EL-0017 #4 As shown in the illustration, what type of starter is illustrated? Illustration EL-0104 #5 In the illustration shown, what would be the functional name for the coil represented as '1S'? Illustration EL-0012 #6 As shown in the illustration, assuming power is available at the control circuit, which listed action will occur FIRST when the "off-run" switch is placed in the "run" position? Illustration EL-0017 #7 Which of the following statements is true concerning the motor controller circuit shown in the illustration? Illustration EL-0004 #8 In the illustration shown, what type of protection is provided the potable pump drive motor? Illustration EL-0043 #9 A three-phase, induction-type motor experiences an open in one phase. Which of the listed automatic protective devices will prevent the motor from being damaged? #10 If the circuit shown in the illustration were energized and operating properly, which of the devices listed would be open? Illustration EL-0007 #11 When a motor is started by the controller shown in figure "C" of the illustration, what circuit components are in the holding current flow path through the control circuit while the motor is in operation? Illustration EL-0010 #12 As shown in the illustrated electrically operated watertight door controller, how is the rotation direction of the door motor reversed? Illustration EL-0115 #13 By what means is the burning of controller contacts due to arcing, when opening, prevented? #14 When rolling over a DC main propulsion motor in local emergency mode or throttle bypass mode, what must be done with the variable rheostat in terms of turning the handle? #15 Which of the following statements is true concerning the operation of modern marine electric drive DC propulsion motors? #16 As shown in figure "B" of the illustration, when the DC motor in figure "A" is operating at minimum speed what are the armature and field characteristics? Illustration EL-0153 #17 Before working on an electric cargo winch master switch or controller, what should be done? #18 Which of the following represents the accepted method of cleaning dust and foreign particles from electrical equipment while limiting damage to electric components? #19 Moisture damage, as a result of condensation occurring inside of the cargo winch master switches, can be reduced by the use of what installed equipment? #20 What damage may occur to the components of a winch master control switch, if the cover gasket becomes deteriorated? #21 The set point current at which a magnetic-type overload relay tends to trip may be increased by turning the dashpot in the 'lower' direction. What effect will this action have? #22 Which of the following methods should be used to dress the face of silver-plated contacts? #23 Grease coatings on electrical contact surfaces increase contact resistance. How should grease accumulations be removed? #24 Which of the following statements is true concerning the cleaning of electrical contacts? #25 What item (or items) constitute routine AC motor controller maintenance? #26 Using the illustrated catalog number selection chart, determine the correct catalog number for a motor starter that meets the following selection criteria: a 3-pole, vertically mounted, NEMA non-reversing starter with an open enclosure rated at 90 continuous amperes, fitted with an electronic overload relay with a standard feature set and an operating coil rated at 120 VAC/60Hz. Illustration EL-0180 #27 Which device will stop the motor shown in the illustration in case of a short-circuit (high current) motor fault? Illustration EL-0080 #28 If you hear a loud buzzing noise coming from a magnetic motor controller, what should you do? #29 The motor fails to start on an attempted startup. With the start button depressed, a voltmeter reading between 1 and 5, as illustrated in figure "A", indicates line voltage available to the control circuit, what should be your next step in the troubleshooting process? EL-0007 #30 Why are motor controllers seldom troubled by grounds?

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