competence 6.1

50問 • 1年前

問題一覧

1. What will happen if a low impedance connection is accidentally created across a charged capacitor within a high-voltage electrical network?

•Large amounts of power can be quickly discharged.

2. When troubleshooting an electronic circuit, a cold solder joint can be located with the aid of an ohmmeter. Once the problem has been located, what should you do next?

•reheat connection with a soldering tool and recheck with an ohmmeter

3. What kind of overload relay that is being actuated by an electromagnetic coil ?

•Magnetic

4. What kind of resistance thermometer utilizes semi-conductor material which have a characteristic of a resistance decrease with temperature increase?

•Thermistor

5. What is the ratio of effective value of the counter EMF in volts to the effective value of the current in amperes?

•inductive reactance

6. The amount of sodium phosphate in treated boiler water can be measured by ?

•Phosphate test

7. What determines the power factor of an electrical distribution system being supplied by a single AC generator?

•By components of the connected load,

8. An instantenous trip type fuse will ?

•open as soon as the loadcurrent exceeds the set point

9. What is the transformer winding where power source is connected?

•Primary winding

10. When a solid-state component of an electronic circuit is mounted to a metalic mass, the general purpose of that mass is to

•act as a heat sink

11. A bus disconnect link is used to isolate?

•the generator ccircuit breaker from the bus

12. After clipping the two leads together, prior to taking a resistance reading with a volt-ohmmilliammeter, the 'zero' setting must be adjusted. ylf you find the adjustment knob will not return the pointer to 'zero'. it is likely an indication of ?

•Batteries are weak

13. Electric propulsion coupling excitation is reduced at slow speed to

•prevent coupling overheating

14. Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation ?

•The winding will burn out.

15. What do you call the emission of electrons from hot bodies?

•radiation effect

16. Which of the following statements describes the significance of ambient temperature in relation to the service life of electronic components?

•Increase ambient temperature decreases the service life of electronic components

17. The first requirement for logical trouble shooting of any system is the ability to

•recognize normal operation

18. What is the use of a magnetic blowout coil in a ship,s crane using DC motor controller contactor ?

•prevent contact melting

19. In SF6 circuit breakers what is the meaning of SF6?

•Sulfur hexafluoride

20. When trouble shooting electronic equipment, you should use a high impedance multimeter

•so as not to load down the circuit and obtain erroneous voltage readings

21. How would you show your understanding to a communication device that allows to talk to each other with the use of a handset, similar to a conventional telephone but without the use of external power?

•Sound-powered teelephone system

22. In a liquid dielectric, which of the following impurity has significant effect in reducing the breakdown strength ?

•Dust

23. A loss of field excitation to an AC generator while operating in parallel will cause to

•lose its load, begin to motorize, trip out on reverse power delay, and possibly overspeed

24. On an engine throttle control system, the auxiliary control circuits are provided with devices to prevent excessive over travel of the pilot valve by the synchronous motor. These devices are called_

•limit switches

25. In a faceplate-type motor starter, the starting arm is held in the 'OFF' position by alan

•strong spring

26. The shunt use in an ammeter should be connected to?

•series with the load and in parallel with the meter movement

27. Which of the following statements concerning analog and digital devices are correct?

•The variables in digital systems are fixed quantities, and the variables in analog systems are contnuous quantities

28. What do you call an instrument that used to measure the specific gravity of the electrolyte in a rechargeable battery ?

•Hygrometer

29. To locate a grounded field coil in a synchronous motor, which of the instruments listed could be used ?

•Megohmmeter

30. You are attempting to parallel two AC generators, and the synchroscope pointer is revolving past in the clockwise direction. What indicates that the frequency of the incoming machine?

•higher than the bus frequency

31. It is defined as the movement of electrical charge (the flow of electrons) through an electrical circuit is called ?

•Current

32. What represents an application of a silicon controlled rectifier?

• To provide DC power for a main propulsion motor.

33. In a circuit that is not energized, which of the listed instrument is used ?

•Ohmmeter

34. How is the operator ensured that he is not in contact with any unearthed conductor before insulation resistance(IR) measurement of a HV system?

•Connct the insulation resistance tester to the conductor with safety earth connection ON.

35. What is the process of breaking up fuel oil into fine particles to ensure good combustion?

•Atomization

36. How do shipboard electrical cables cross-sectional area express?

•circular mills

37. RTD type sensor utilizes which principle in temperature measurement?

•Wheatstone bridge principle

38. What is the first step in removing a generator from parallel operation.

•Decrease the governor setting on the l'off goingl' generator.

39. Which of the following indicate when paralleling two alternators, the synchronizing lamps remain lit as the synchroscope pointer approaches the 0° position?

•synchroscope is defective or broken

40. What cause the main feed pump which can handle high temperature water without becoming vapor bound?

•Required net positive suction pressure is designed into the system

41. What is the degree angle when the voltage and current are out of phase so that the true power is equal to zero?

42. The following are main things you should ccheck when synchronizing a generator except for?

• current

43. What type of widely used thermocouple, also termed as Ni-Chromium/Ni-Alumel, with enhanced reliability, preciseness, inexpensive and operate at temperature ranges between -270 to 1,260 degc?

•Type к

44. Ammeters and voltmeters use in a sinusoidal AC power system indicates which of the following values of the waveforms measured?

•root means square value

45. The following are rating of circuit breakers except

•Rated short ionization current

46. a triac thyristor functions as a control device and is basically

•two-back-to back SCR's with a common gate lead

47. In a three-phase electrical system, three ground detecting lamps are provided. One lamp goes dark and the others increase in brightness. When the test button is pushed, all lamps have equal illunination. You should called that

•There is a ground on the line with the dark lamp

48. While starting a synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. What is this an indication of?

•motor has started properly

49. When using an ohmmeter to test a semi conductor diode, you find a low resistance in both forward and reverse bias direction. This indicates that the diode is,

•Short

50. On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had cut-out from synchronization with the propulsion generator ?

•Excessive vibration of the vessel

competence 4.1

ERNO ENRIQUE JOMENTO · 3回閲覧 · 50問 · 1年前

competence 4.1