MET ONLINE.docx

7/30/2019 MET ONLINE.docx

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MARINE ELECTRO TECHNOLOGY

1. Time delayed or delayed action-type fuses are designed to _____________.

(A)prevent grounds in branch circuits(B) prevent opens in motor circuits

(C) permit momentary overloads without melting

(D) guard lighting and electronic circuits

Briefly justify your answer

2. Silicon diodes designed for a specific reverse breakdown voltage, become useful as an

electronic power supply voltage regulator, called _____________.

(A) tunnel diodes

(B) hot-carrier diodes

(C) compensating diodes

(D) Zener diodes


3. Which of the following statements best describes the material known as varnished cambric?

(A) Felted asbestos sealed with varnish.

(B) Cotton cloth coated with insulating varnish.

(C) Rubber insulation coated with a layer of tin.

(D) Paper impregnated with mineral oil, specially wrapped with nonmetallic tape, and coated

with varnish.


4. A synchronous motor maintains synchronism with the rotating field because _____________.

(A) field strength varies directly with rotors lIp

(B) DC current applied to the rotor coils causes the rotor magnets to lock in with the rotating

flux of the stator

(C) the stator poles are dragged around due to the flux created by the excitation current(D) the stator flux rotates in the opposite direction


5. What is the maximum allowable primary current of a 2 KVA step-down transformer with a

four to one turns ratio if connected across a 440 volt line?

(A) 1.1 amps

(B) 4.5 amps

(C) 18.1 amps

(D) 27.7 amps

Give Calculation to Justify your Answer

6. The part of a fuse that melts and opens the circuit is made of _____________.

(A) Copper and antimony

(B) Steel and Babbitt

(C) Aluminum or beryllium alloy

(D) Zinc or an alloy of tin and lead


Answers for Question No. 1 Correct Answer : C

Answers for Question No. 2 Correct Answer : D

Answers for Question No. 3 Correct Answer : B



Answers for Question No. 6 Correct Answer : D

(B) 1. Which of the following statements is true concerning a poly-phase synchronous propulsionmotor?


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A. The motor is started as an induction motor.

B. Resistance is gradually added to the rotor circuit.

C. The starting current is held below the rated current.

D. The field winding is energized for starting purposes only.

2. When reading electrical motor controller diagrams, it helps to know that ____________.

A. current paths in the

control circuit are drawn

as heavy lines and in the

power circuit as lighter

lines

B. current paths in the

power circuit are drawn

as heavy lines and incontrol circuit as lighter

lines

C. circuits subject to 500

volts or greater are

drawn as heavy lines and

below 500 volts as lighter

lines

D. circuits subject to 500

volts or greater are

drawn as light lines and

below 500 volts as heavy

3. Alternating current circuits develop resistance, inductance and

capacitance. The inductance of a coil is expressed in

_____________.

A. ohms B. mhos C. henrys D. farads

4. Large cable sizes are formed as individual conductors that may

be comprised of several smaller strands to __________.

A. obtain the flexibility

required for easy

handling

B. reduce the overall weight

of the wire run

C. reduce the number of

supports needed for a

horizontal overhead run

D. all of the above

5. Which of the following is having Di-Electric Constant 80?

A. Air B. water C. Mica D. Caster oil


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6. Where a thermal-acting breaker is required to be used in an area

of unusually high, low, or constantly fluctuating temperatures, an

ambient compensating element must be used. This element

consists of a ______________.

A. cylindrical spring on the

contact arm

B. conical spring on the

contact arm

C. second bimetal element

D. second electromagnet

7. Which of the following precautions should you take when

securing propulsion generators and motors for an extended

period of time?

A. Disconnect the brushpigtails from their

contacts and circulate

air through the units.

B. Disconnect the brush

pigtails from their

contacts and discharge

carbon dioxide into the

units to keep them dry.

C. Lift the brushes from

commutator collector

rings and use the built-inheater to prevent

moisture accumulation.

D. Lift the brushes from

commutator collector

rings and circulate cool

dry air through the units.

8. The direction of magnetic flux changes when the direction of current is reversed.

True / False

9. In a Transistor

A. PNP and NPN are two basic types

B. Emitter,Collector and Base are the basic Elements.

C. Collector separates Base and Emitter

D. Emitter separates Base and Collector

9. 9. In a P-Type Semiconductor, the majority current Carriers are ___________.

10. In a Control Loop System, having Zero(0) Positive Real Values are called____________.

11. If a Motor is not rotating in the E/R, you will carry out the following Checks (multiple choice,

3 Questions of same type but Options were different )

A. Check for the isolation


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B. Rotate the Coupling with your hand

C. Check for the Circuit breaker

D. Remove the fuses

E Look for the Overload Trip

F. Visually Inspect the motor terminals

G. Visually Inspect the Starter Terminals

H. Carry out Infinite Resistance Test

14. Calculate the Velocity of the conductor (up to 0 decimal places), if terminal voltage is 2.2 V/m

and the magnetic field strength is 0.2 T.

15. Calculate the frequency of the motor ( up to 0 decimal places),, if the speed if 4800 Rpm and

number of Poles is 2.

16. If the resistance of any coil is 120 Ohm. Calculate the Resistance (up to 0 decimal places),

when its Length is increased by 20% and its Diameter is increased by 50%.

17. What is the power in a Resistor in Milli Watts (up to 0 decimal places), having Resistance of

12 Ohm having a Potential Difference of 3 V.

18. Resistance of a wire is increased if the Length is __________ and Area is ____________.

19. Arrange the following in Increasing Order of their Doping Strength.

A. Collector, Emitter, Base

B. Base, Emitter, Collector

C. Emitter, Base, Collector

D. Emitter, Collector, Collector Base, Collector, Base

20. Which of the listed precautions should be taken when cleaning

the internals of a motor with compressed air?

A. Open the machine onboth ends so as to allow

the air and dust to

escape.

B. Be certain that the circuit

breaker is opened and

tagged on the feeder

panel.

C. Be certain that the air is

clean and as dry as

possible.

D. All of the above


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MOTOR RATING GIVEN IN KWHR ,RUN FOR 36 DAYS , FIND POWER CONSUMED IN KWHR ?

2) N = ((120*F) / P)

3) E = B*L*V

4) R = ((RHO * LENGTH)/ CROSS SECTION AREA)

5) FIND EFFECTIVE CAPACITANCE IF 4 CAPACITANCE ARE IN SERIES

6) POLYPHASE MOTOR FAILS TO START WHAT TO DO ?

7) MOTOR MAINTENANCE WHAT ALL THINGS TO DO ?

8) SEMICONDUCTOR BORON ADDED WHAT WILL HAPPEN ?

9) SEMICONDUCTOR CURRENT CARRIERS ?

10) A molded-case breaker provides protection against short circuits by using a/an ____________.

11) THERMAL CIRCUIT BREAKER ?

12) PN DIODE ADVANTAGE OVER VACUUM DIODE ?Best AnswerMuch lower operating voltages, less power dissipation, less complex (but more complicated)construction, smaller size, less power required for operation, greater potential for integration intointegrated circuits.

1)13) WHAT IS TRANSDUCER ?

14) IN SQUIRREL CAGE INDUCTION MOTOR SPEED DEPENDS UPON ?

14) PROPULSION MOTOR REQUIREMENT ?

15) DATA LOGGER REFRIGERATION ?

16) DIELECTRIC CONSTANT OF WATER ?

17) FILL IN THE BLANK RELATED TO SEMI CONDUCTOR

18) QUESTION RELATED TO DIODE CURRENT FORWARD BIASED

19) WHAT IS PIV

20) WIRES WHY MULTIPLE STANDARD

21) GENERATOR PARALLEL CONDITION

22) When reading electrical motor controller diagrams, it helps to know that ____________.(ANS

- current paths in the power circuit are drawn as heavy lines and in control circuit as lighter lines

)

23) UNIT OF INDUCTANCE ?

24) TRUE OR FALSE ...RELATING TO PRICIPLE OF ELECTROMAGNETIC INDUCTION

?

25) Tightly knit metal braid wire can be used with a printed circuit board when ___________.

USCG - AROUND 5 QUESTIONS

NUMERICALS - 4 QUESTIONS


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1. Highest di electric constant is of- Air gap / Vaccum

2 Thin lazing wire is for???

3 The direction of magnetic flux changes when the direction of current is reversed. True

/ False

4 In control loop system having zero positive real values are ------------

2) The dielectric constant(relative permittivity) is the ratio of the permittivity of a substance tothe permittivity of free space(vaccum). So dilec cnst of vaccum is 1, Air- 1.0006, PTFE 2,

Glass- 4.9-7.5

3)4) I literally think u mean lacing wire,thin lacing wire traditionally made f waxed linen s used to

bind together a group f cables, avoiding d handling problems f cables.

5)6) Remember d Right hand grip rule, Grab d wire in ur right hand wid ur thumb pointing in d

direction of current and ur fingers wrapping d wire in d direction f d magnectic field. Yes, ddirection changes when d current is reversed.

7)8) Control loop system having zero or positive real values are UNSTABLE

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