U.S.C.G. Merchant Marine Exam DDE – 1000/4000 HP Q634 ...€¦ · National Maritime Center Serving Our Nation’s Mariners. U.S.C.G. Merchant Marine Exam . DDE – 1000/4000 HP

National Maritime Center Serving Our Nation’s Mariners

U.S.C.G. Merchant Marine Exam

DDE – 1000/4000 HP

Q634 General Subjects

(Sample Examination)

Page 1 of 22 Q634 General Subjects

8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9

Choose the best answer to the following Multiple Choice Questions

1. As shown in figure "A" of the illustrated block diagram of a central operating system configured for direct digital control, what does the output system block "ANALOG A/D" represent? Illustration EL-0095

o (A) It receives analog outputs from the analog device sensors and conditions these as analog signals for CPU processing.

• (B) It receives analog outputs from the analog device sensors and converts these to digital signals for CPU processing.

o (C) It receives digital outputs from the binary device sensors and conditions these as digital signals for CPU processing.

o (D) It receives digital outputs from the binary device sensors and converts these to analog signals for CPU processing.

If choice B is selected set score to 1.

2. Which of the following compressors would be used for a dead ship start-up of a ship's service diesel-generator on a motor ship?

• (A) Emergency air compressor o (B) Topping air compressor o (C) Ship's service air compressor o (D) Starting air compressor

If choice A is selected set score to 1.

3. Which of the following statements represents the proper criteria to decide when to drain a filter/moisture separator as used in a ship's service air system hose station?

o (A) The bowl should be drained whenever moisture droplets appear in the bowl. o (B) The bowl should be drained daily with no need to check the moisture level. o (C) The bowl should be drained after the bowl completely fills with moisture. • (D) The bowl should be drained before the moisture level reaches the lower baffle.

If choice D is selected set score to 1.

4. In a closed-loop process control system, what statement concerning feedback is true as it relates to stability and the direction of error displacement?

o (A) Positive feedback is used to minimize instability by pushing the system in the opposite direction as the error displacement.

• (B) Negative feedback is used to minimize instability by pushing the system in the opposite direction as the error displacement.

o (C) Negative feedback is used to minimize instability by pushing the system in the same direction as the error displacement.

o (D) Positive feedback is used to minimize instability by pushing the system in the same direction as the error displacement.



8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9 5. According to the illustration, which of the following conditions would most likely cause pump "A" to

short cycle? Illustration GS-0173

• (A) The hydro-pneumatic expansion tank is operating with an insufficient air charge. o (B) The hydro-pneumatic tank is operating with a low water level. o (C) A low water level exists in the potable water storage tank. o (D) Pump "A" wearing rings have excessive clearance.


6. Which term represents the ability of a speed control governor to maintain prime mover speed without hunting?

o (A) Promptness • (B) Stability o (C) Deadband o (D) Sensitivity


7. If the bearings of a piece of machinery are force-fed by a pressure feed lubricating oil system, which statement is true?

• (A) The lube oil pump draws a suction on the lube oil reservoir/sump and discharges directly to the bearings. The return oil then gravity drains to the lube oil reservoir/sump.

o (B) The lube oil pump draws a suction on the lube oil gravity tank and discharges directly to the bearings. The return oil then gravity drains to the lube oil gravity tank.

o (C) The lube oil pump draws a suction on the lube oil reservoir/sump and discharges directly to the bearings. The return oil then gravity drains to the lube oil gravity tank which overflows to the lube oil reservoir/sump.

o (D) The lube oil pump draws a suction on the lube oil reservoir/sump and discharges to the lube oil gravity tank. The oil then gravity feeds the bearings and the return oil drains to the lube oil reservoir/sump.


8. Permanent centrifugal pump shaft damage due to erosion, corrosion, and wear at the stuffing box is usually prevented by __________.

o (A) internally flooded lantern rings o (B) wearing rings • (C) renewable sleeves o (D) a hardened sprayed metal coating

If choice C is selected set score to 1.


8/22/2019


9. The line labeled "C", as shown in the illustration, would be identified as the ______. Illustration GS-0175

• (A) clean water inlet line o (B) processed water outlet line o (C) waste oil discharge line o (D) oily bilge water inlet line


10. What provision is made for sea chests for removal of solid debris restricting the entry grating into the sea chest of a machinery space sea water cooling system?

o (A) The debris is continuously removed by blowing the sea chest clear with either compressed air or steam by cracking open the blow valve, as appropriate.

o (B) The debris is continuously removed by draining the sea chest clear by cracking open a drain valve located at the bottom of the sea chest.

• (C) The debris may be removed by blowing the sea chest clear with either compressed air or steam, as appropriate.

o (D) The debris may be removed by draining the sea chest clear by opening a drain valve located at the bottom of the sea chest.


11. What is the pressure and condition of the refrigerant entering the receiver of a refrigeration system?

o (A) superheated high-pressure vapor o (B) subcooled low-pressure liquid • (C) subcooled high-pressure liquid o (D) superheated low-pressure vapor


12. Why can CFC or HCFC refrigerants leaking into a confined space or in limited surroundings cause suffocation?

• (A) Refrigerants are heavier than air and displace oxygen. o (B) Refrigerants lighter than air will rise. o (C) Refrigerants obnoxious odor prevents breathing. o (D) Refrigerants contain an acidic substance.



8/22/2019


13. What is another name for the "collision" bulkhead?

o (A) After peak bulkhead • (B) Forepeak bulkhead o (C) Forward engine room bulkhead o (D) After engine room bulkhead


14. In a two-stage centrifugal air conditioning system such as the one illustrated, the liquid refrigerant passes from the condenser directly to what component? Illustration RA-0064

• (A) economizer o (B) expansion valve o (C) chiller o (D) evaporator


15. In an air conditioning system set up as shown in the illustration, as the room humidistat initiates the lowering of the humidity of the conditioned supply air to a space, the actual process is accomplished by what means? Illustration RA-0009

• (A) lowering the cooling coil temperature and raising the reheater temperature o (B) raising the cooling coil temperature and lowering the reheater temperature o (C) lowering both the cooling coil temperature and the reheater temperature o (D) raising both the cooling coil temperature and the reheater temperature


16. The safety heads of most large reciprocating compressors used in refrigeration systems are held in place by what means?

o (A) discharge pressure in the relief valve return line o (B) tack welding on the sides o (C) large Teflon gaskets • (D) heavy coil springs


17. The "tare weight" of a refrigerant storage cylinder refers to what weight?

o (A) the maximum weight of the refrigerant allowed o (B) the total weight of a fully charged cylinder • (C) the weight of an empty cylinder o (D) the weight of a cylinder AND its current contents



8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9 18. Capacity control of a centrifugal refrigeration compressor can be accomplished by what means?

o (A) varying the position discharge bypass valve o (B) varying the speed of the compressor o (C) varying the position of the prerotation inlet vanes • (D) all of the above


19. Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where externally adjustable superheat and a replaceable power element are both desired? Illustration RA-0006

o (A) A • (B) B o (C) C o (D) D


20. The most cost-effective method of recovering refrigerant from a low-pressure chiller with more than 500 lbs. of refrigerant and to meet EPA requirements is to recover the refrigerant using what protocol?

• (A) liquid recovery using a liquid pump, followed by vapor recovery using a vacuum pump based recovery unit

o (B) recovery using a liquid pump only o (C) vapor recovery using a vacuum pump based recovery unit followed by liquid recovery using a

liquid pump o (D) recovery using a vacuum pump based vapor recovery machine only


21. How should small appliances with less than three pounds of refrigerant be charged with refrigerant?

o (A) either vapor or liquid charged o (B) liquid charged • (C) vapor charged o (D) initially liquid charged and then topped with a vapor charge


22. The output volume of a positive fixed displacement pump can be changed only by __________.

o (A) moving the shaft trunnion block o (B) moving the slide block and rotor • (C) changing the speed of the pump o (D) changing the angle of the tilting plate



8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9 23. Energy losses occurring in a hydraulic system are ultimately absorbed by the __________.

o (A) reservoir expansion chamber o (B) hydraulic piping flexibility o (C) fluid as friction • (D) atmosphere as heat


24. A two-stage hydraulic pump unit is used to __________.

o (A) establish two individual flows to segregated segments of one system o (B) produce twice the flow rate than if only one element were to be used o (C) supply two individual flows to the same segments of the system if one of the pump elements

were to fail • (D) develop the same flow rate across both pump elements with the discharge pressure of the

second pump element being substantially higher than that of the first stage


25. A precharged bladder-type accumulator used in a hydraulic system, can be potentially dangerous if __________.

• (A) compressed air is used rather than an inert gas o (B) the bladder contacts the top of the poppet o (C) the inert gas is exposed to hydraulic oil o (D) it is precharged with dry nitrogen


26. Four incandescent lamps are connected in series in a single circuit. If one of the lamp filaments burns out, what will happen to the other lamps?

• (A) all go out o (B) become dimmer o (C) no change in brightness o (D) become brighter


27. Which statement is true concerning the total power consumed in a parallel circuit?

o (A) The total power is the sum of the powers consumed by each load (resistor) divided by the number of loads.

o (B) The total power is always less than the power consumed by the smallest load. o (C) The total power is never more than the power consumed by the largest load. • (D) The total power is equal to the sum of the powers consumed by each individual load.



8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9 28. If a digital multimeter set up to measure AC volts reads low value, but constantly changing "ghost

voltages" when its leads are disconnected, what does this indicate?

o (A) Stray electromagnetic fields from electrical equipment exist in the air. o (B) The digital multimeter test leads are acting as an antenna. o (C) The digital multimeter AC voltage range is at its lowest value. • (D) All the above conditions must exist.


29. In preparing a battery-operated digital megohmmeter (resistance tester) for use, what statement is true?

o (A) The circuit or circuit component under test must be energized, AND the megohmmeter test voltage must be set to a value less than the equipment exposure voltage.

o (B) The circuit or circuit component under test must be de-energized, AND the megohmmeter test voltage must be set to a value less than the equipment exposure voltage.

• (C) The circuit or circuit component under test must be de-energized, AND the megohmmeter test voltage must be set to a value equal to or greater than the equipment exposure voltage.

o (D) The circuit or circuit component under test must be energized, AND the megohmmeter test voltage must be set to a value equal to or greater than the equipment exposure voltage.


30. 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?

o (A) dirty or acid-wet tops and sides of batteries • (B) accumulation of sediment within the cells due to excessive overcharging and discharging o (C) sulfation of the plates due to consistent undercharging or leaving the battery in a discharged

state o (D) lime accumulation on both the positive and negative terminal posts


31. The leads from an ohmmeter are attached to the leads of the opposite ends of an AC induction motor stator coil. If a reading of infinity (OL) is obtained, what does this indicate?

o (A) shunted stator coil • (B) open stator coil o (C) grounded stator coil o (D) shorted stator coil



8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9 32. As shown in figure "B" of the typical ground fault relay shown in the illustration, what statement

concerning the leakage current setting adjustment is true? Illustration EL-0223

• (A) Setting the leakage current for too low a value may increase the likelihood of nuisance trips and setting the leakage current for too high a value may result in incidental damage due to a ground fault.

o (B) Setting the leakage current for too high a value may increase the likelihood of nuisance trips and setting the leakage current for too low a value may result in incidental damage due to a ground fault.

o (C) Setting the leakage current for too high or too low a value may increase the likelihood of nuisance trips.

o (D) Setting the leakage current for too high or too low a value may result in incidental damage due to a ground fault.


33. What effect will increasing the power source frequency have on the capacitive reactance of a capacitive circuit?

o (A) it will increase the capacitive reactance of the circuit o (B) it will not have any impact on the capacitive reactance of the circuit • (C) it will decrease the capacitive reactance of the circuit o (D) it is impossible to predict the effect on the capacitive reactance


34. Three 12 volt, lead-acid, batteries connected in series will develop how many volts?

o (A) 12 volts o (B) 24 volts • (C) 36 volts o (D) 48 volts


35. Which of the following motors has a frame configuration for solid base mounting only? Illustration EL-0184

• (A) A o (B) B o (C) C o (D) D



8/22/2019


36. What is the name of the type of motor control circuit that will not permit automatic restarting after power is restored, following a power failure?

• (A) low voltage protection o (B) reduced voltage restart o (C) overload lockout o (D) low voltage release


37. Which of the substances listed can be used to shield sensitive equipment from static magnetic fields?

• (A) Iron o (B) Mica o (C) Bakelite o (D) Glass


38. Which of the listed temperature measuring devices installed on a large turbo-electric alternating current propulsion generator would be the most reliable for monitoring generator temperatures to avoid premature winding insulation failure?

• (A) Temperature sensors inserted in the stator slots for measuring stator winding temperature. o (B) Temperature sensors measuring the temperature of the cooling water associated with the

generator air cooler. o (C) Temperature sensors measuring the temperature of the cooling air associated with the

generator air cooler. o (D) Current transformers are the most reliable means of monitoring generator temperatures.


39. 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, 60 Hz with a total plant generating capacity of 10000 kW?

o (A) exactly 60 Hz must be supplied from shore, with no deviation permitted o (B) exactly 450 volts must be supplied from shore, with no deviation permitted • (C) shore power phase sequence must agree with that of the ship o (D) shore power must be capable of delivering a total of 10000 kW



8/22/2019


40. How are fuses usually rated?

o (A) watts only o (B) amps only o (C) volts and amps only • (D) volts, amps, and interrupting capacity


41. What is the basic similarity between a circuit breaker and a fuse?

o (A) after a short or overload condition, both must be reset to re-energize the circuit o (B) after a short or overload condition, both have to be replaced before the circuit can be re-

energized • (C) after a short or overload condition, both should open to de-energize the circuit o (D) a circuit breaker and a fuse have no similarities


42. Which of the following fixed temperature heat-actuated fire detectors can be reused after it has detected a fire?

o (A) liquid expansion o (B) thermostatic cable • (C) bimetallic snap-disc o (D) fusible metal


43. Which of the listed pressure control valves would be used to permit the completion of one action of a hydraulic system before a second action would be permitted?

• (A) Sequence valve o (B) Pressure-reducing valve o (C) Counterbalance valve o (D) Unloading valve


44. In accordance with 33 CFR Subchapter O (Pollution), which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flush water at ambient air pressure and temperature?

o (A) Type I o (B) Type II • (C) Type III o (D) Type IV



8/22/2019

Q634 General Subjects U.S.C.G. Merchant Marine Exam DDE-1000/4000 HP Illustrations: 9 45. In an electro-hydraulic steering system, damage due to rudder shock is prevented by __________.

o (A) buffer springs • (B) relief valves o (C) oil flowing through the pumps o (D) dashpots


46. What is used to protect a direct sensing steam pressure gauge from damage from contact with steam?

o (A) The installation of a damping needle valve in the entrance to the gauge. o (B) The installation of thermal insulation on the gauge. • (C) The installation of a siphon tube (pig-tail) oriented vertically in the entrance to the gauge. o (D) The installation of a siphon tube (pig-tail) oriented horizontally in the entrance to the gauge.


47. In application, which of the listed sealing devices is most similar to an O-ring?

o (A) V-ring o (B) U-ring • (C) Quad ring o (D) Cup seal


48. Which of the following statements is true concerning the gauge labeled "A" of the illustrated gauge manifold set? Illustration RA-0001

o (A) The gauge labeled "A" is a standard pressure gauge and is usually color-coded blue. o (B) The gauge labeled "A" is a standard pressure gauge and is usually color-coded red. o (C) The gauge labeled "A" is a compound gauge and is usually color-coded red. • (D) The gauge labeled "A" is a compound gauge and is usually color-coded blue.


49. Which of the drill sets listed would commonly be referred to as a 'Jobbers Set'?

o (A) A set of fractional size drills from 1/2'' to 2''. • (B) A set of fractional size drills from 1/16'' to 1/2''. o (C) A set of lettered size drills from A to Z. o (D) A set of numbered size drills from 1 to 60.



8/22/2019


50. Which of the following bilge pumping applications would most likely use a non-automated centrifugalpump under manual supervision?

o (A) Machinery space bilgeso (B) Engine room bilges• (C) Dry cargo-hold bilgeso (D) Shaft alley bilges



8/22/2019

National Maritime Center

Serving Our Nation’s Mariners

10/9/2018

EL-0095

Adapted for testing purposes only from HUNT, Modern Marine Engineer’s Manual, Volume II, 3rd Edition

Copyright © 2002 by Cornell Maritime Press, Inc.

Further reproduction prohibited without permission Page 14 of 22




10/10/2018

EL-0184

Adapted for testing purposes only Further reproduction prohibited without permission Page 15 of 22




10/11/2018

EL-0233 Relay and PLC Logic Compared

Fig. A and B: Adapted for testing purposes only from

HERMAN, Industrial Motor Control, 6th Edition

Copyright © 2010 by Delmar, Cengage Learning

Further reproduction prohibited without permission

Fig. C and D: Adapted for testing purposes only from

BOLTON, Programmable Logic Controllers, 5th Edition

Copyright © 2009 by Elsevier Ltd.

Further reproduction prohibited without permission


National Maritime Center Serving Our Nation’s Mariners

9/27/2018

GS-0173

Adapted for testing purposes only from ROWEN, Introduction to Practical Engineering, Volume 2

Copyright © 2005 by the Society of Naval Architects and Marine Engineers

Further reproduction prohibited without permission Page 17 of 22 Q634 General Subjects

National Maritime Center Serving Our Nation's Mariners

9/27/2018

GS-0175

Adapted for testing purposes only from Heli-Sep Model 550/OCD Technical Manual

Copyright © by Coffin World Water Systems



Serving Our Nation's Mariners

9/17/2018

RA-0001

Adapted for testing purposes only from ALTHOUSE, Modern

Refrigeration and Air Conditioning

Copyright © 1992 by The Goodheart-Willcox Company, Inc.

Further reproduction prohibited without permission Page 19 of 22




9/17/2018

RA-0006

Adapted for testing purposes only




9/17/2018

RA-0009

Adapted for testing purposes only from HARRINGTON, Marine Engineering

Copyright © 1992 by The Society of Naval Architects and Marine Engineers




9/18/2018

RA-0064

Adapted for testing purposes only from HARBACH, Marine Refrigeration and Air-Conditioning

Copyright © 2005 by Cornell Maritime Press


Documents

U.S.C.G. Merchant Marine Exam DDE – 1000/4000 HP Q634 ...€¦ · National Maritime Center Serving Our Nation’s Mariners. U.S.C.G. Merchant Marine Exam . DDE – 1000/4000 HP