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

USCG Marine Electrical Systems (Set 35)

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Question 1 of 30

What is the best method of determining the state of charge of a lead acid storage battery?

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30 MCQs

#1 What is the best method of determining the state of charge of a lead acid storage battery? #2 Which of the following activities occurs during the charging process of a lead-acid storage battery? #3 Why must caution be exercised during the charging of lead-acid storage batteries? #4 What statement is true concerning the actual mixing process and the container used when mixing electrolyte for a lead-acid storage battery? #5 What statement is true concerning the charging a 100 amp-hour lead-acid battery? #6 Which of the following statements concerning Nickel-Cadmium batteries is true? #7 You are reconnecting a three-phase induction motor to the supply line. To prevent possible damage to the load, due to the wrong direction of rotation, what should be done? #8 What is a useful instrument for checking 3 phase A.C. motor performance by measuring possible unbalanced currents? #9 Suppose it is desired to connect a dual voltage three phase squirrel cage induction motor for low volts, but it is undetermined whether the nine-lead motor is internally configured for wye or delta configuration. Using an ohmmeter, the motor itself with leads disconnected, and the illustration as a guide, what statement is true? EL-0134 #10 Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? #11 When using the test set-up shown in figure "A" of the illustration, besides the motor windings and the motor feeder cable, what circuit components are actually being meggered? EL-0027 #12 Large machines undergoing a resistance insulation testing using a megohmmeter should be discharged to remove any accumulated electrostatic/capacitive charge stored. When should this discharge be performed? #13 When you are making a high potential test (megger) on the motor coils of repaired electrical machinery to ground. What would a low resistance reading indicate? #14 Using the temperature correction factor for the winding insulation temperature graph shown in the illustration, what would be the correction factor and the corrected temperature to 40 degrees C for a motor with a insulation resistance of 4 megohms measured at 50 degrees C? EL-0046 #15 Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments of a DC motor? #16 In general, what can cause D.C. propulsion motor brush sparking to be excessive? #17 What should be used in the cleaning of a D.C. propulsion motor's commutator face? #18 How is the seating the brushes on a DC motor commutator first accomplished? #19 D.C. propulsion motor brush pressure depends on the brush grade used. In practice with what device is the proper brush pressure established? #20 With regard to the maintenance of electrical generating machines with insulated pedestal bearings, what practice should be avoided? #21 Rotor-to-stator air gap readings should be periodically taken for electrical generation equipment. What is the best tool to use to take these measurements? #22 If rotor-to-stator air gap readings for an electrical generating machine have changed significantly from the last reading, what should be checked? #23 In performing routine maintenance of a ship's service alternator, what should be included? #24 How may chattering of the collector/slip ring brushes on a generator be remedied? #25 Which of the following materials is recommended for burnishing the slip rings of an alternator after grinding or turning? #26 Which of the following statements, concerning the cleaning maintenance of a brushless generator, is correct? #27 When an alternator is to remain idle for even a few days, what should be done? #28 While inspecting the copper commutator bars of a DC generator, you notice a chocolate brown film covering the bars. What should be done? #29 As the brushes ride on the commutator of a DC generator, eventually mica ridges will form between the bars causing sparking and chipping of the brushes. When this happens the mica must be undercut. To what depth is the mica undercut? #30 Referring to the illustration of possible brush holder mounting configurations, which figure is the correct method of configuring the brushholders on a DC generator? EL-0057

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