Pass Benchmark: 70% (21/30) • Standard: USCG NMC / 46 CFR
USCG Marine Electrical Systems (Set 39)
30:00
|Question 1 of 30
Question Navigator
Correct Incorrect Pending Starred
Question 1 of 30
Prior to using an analog multimeter set up as an ohmmeter, the leads are purposely shorted together. Which of the following actions should be taken if, when adjusting to 'zero' ohms, the indicating needle cannot be returned to 'zero' on the scale?
Browse Questions in Set 39
30 MCQs #1 Prior to using an analog multimeter set up as an ohmmeter, the leads are purposely shorted together. Which of the following actions should be taken if, when adjusting to 'zero' ohms, the indicating needle cannot be returned to 'zero' on the scale? #2 While troubleshooting a circuit in an engine room central control console, a resistor is suspected of being faulty. Which of the following precautions must be observed if an analog or digital multimeter set up as an ohmmeter is to be used to check its value? #3 If you disconnect and arrange both ends of a conductor of a multi-conductor cable without any contact between the individual conductors, what would a low ohmic value between the ends of a single conductor indicate? #4 Which of the listed statements is correct when using an digital multimeter set up as an ohmmeter? #5 When testing a capacitor with an digital multimeter set up as an ohmmeter, what would be the indication on the display when testing an initially discharged capacitor in good condition? #6 A digital multimeter, set up as a milliammeter on the 100 milliamp scale, is known to have an accuracy of plus or minus 2%. A display reading of 10.0 milliamps would indicate an actual line current between what two values? #7 If a digital multimeter set up to measure AC volts reads slightly above 'zero' when its leads are disconnected, what is this a result of? #8 Under what circumstance would a hand-held portable phase sequence indicator be used should the main switchboard mounted fixed phase sequence indicator be inoperative? #9 In what situation would an electrical phase sequence indicator be useful? #10 Using the portable harmonic analyzer shown in figure "A", if the clamp-on test lead is connected as shown in figure "C" of the illustration, what is being measured? EL-0110 #11 Which of the listed battery charging circuits is used to maintain a wet-cell, lead-acid, storage battery in a fully charged state during long periods of disuse? #12 What will be the freezing point of the electrolyte in a fully charged lead-acid battery as compared to a discharged battery? #13 What should be performed as routine maintenance of lead acid batteries? #14 Which of the processes listed occurs during the charging of a lead-acid storage battery? #15 To test the state of charge of a nickel-cadmium battery, what should be used? #16 Which of the problems listed will occur if a lead-acid battery is allowed to remain in a discharged condition for a long period of time? #17 What is the standard procedure for maintaining the charge in an emergency diesel starting battery by trickle charge? #18 Which of the substances listed should be applied to battery terminals to help prevent corrosion? #19 What is practice is considered conducting proper storage battery maintenance? #20 What condition associated with a lead-acid battery cell can cause the plates to partially short-out and cause the cell to fail to hold a charge. #21 What would cause a lead-acid battery to become hotter than normal during charging? #22 When troubleshooting a lead-acid storage battery, what is the best method for detecting a weak or dead cell? #23 Which of the problems listed will occur if a lead-acid battery is allowed to remain in a discharged condition for a long period of time? #24 After a black out onboard and once ships power has been restored, the engine room supply fans must be started manually. What characteristic of the electrical circuit for the supply fans cause this requirement? #25 What is the advantage of using an auto-transformer starter? #26 What is the advantage of using a star delta starter? #27 If a motor is direct-on-line started with the stator winding star connected, it will only take a fraction of the starting current that it would take if the windings were delta connected. What is that fraction? #28 You direct the electrician to take quarterly insulation resistance reading of the ship's critical motors. What additional directions would you give to ensure accurate readings are taken that will allow for the logical comparison of prior and current readings? #29 The design Power Factor (PF) of a vessel's electrical system is generally 0.8 - 0.9. The system's greatest load is inductive. One notices a slow, gradual decrease, over time, in the PF, from normal/design. What can one do on board to maintain the normal, design PF and thus maintain electrical system's efficiency? #30 The electrical officer is about to check the insulation resistance. When advice should you give to him as to what temperature and or when he should check the motor insulation?
Question Discussion & Notes
0Have a doubt, memory trick, or exam update? Share your insights with fellow mariners.
Loading mariner discussions...