Тест по Engine Department about Electrical Electronic & Control (CES v6.0)

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Right answers:
1

A 5 V DC source has an internal impedance of 0,2 ohms. When a load of 2,3 ohms is applied what voltage will be measured at the source terminals?

Your answer is correct:

4,6 V.
2

A triac is used to provide temperature control of an oven. The galley complain that the oven only reaches approximately 50 % of demanded temperature. Which of the following is a likely cause?

Correct answer:

One of the main switching elements in the triac has failed.

Your Answer:

Connection between the demand knob and the triac gate terminal has gone open circuit.
3

Which of the following measures is to be taken when working with batteries?

Your answer is correct:

Recharge batteries immediately after discharge.
4

Which of the following is an application of a piezoelectric sensor?

Your answer is correct:

Accelerometer.
5

What is the minimum starting requirement of an emergency generator?

Your answer is correct:

2 separate starting devices each with stored energy capable for at least 3 consecutive starts.
6

When considering instrumentation systems, what is the meaning of the expression “dead-band”?

Your answer is correct:

The controller will not react to a process change in this range.
7

Which of the following is the minimum acceptable value of insulation resistance for High Voltage equipment?

Your answer is correct:

1 M Ohms.
8

In tanker operations, there will be some areas and zones where flammable or explosive vapour, gas or dust may be expected. Such areas are classified as hazardous. What is meant by hazardous area Zone 1?

Your answer is correct:

Flammable mixture is not continuously present, but will be present during normal operations.
9

Which of the following methods may a diode be tested by?

Your answer is correct:

Use a Digital Multi-Meter set to measure ohms in forward and reverse directions.
10

When performing electrical testing of a three phase motor, insulation resistance measurements may be influenced by which of the following?

Your answer is correct:

Temperature, humidity and surface contamination.
11

Flow irregularities in pipes are not caused by:

Your answer is correct:

Straight pipe.
12

Which of the following is not a mode of a closed loop control?

Your answer is correct:

Manual.
13

A Multimeter is not suitable to measure:

Your answer is correct:

Power.
14

Continuity testing of a delta connected three phase induction motor yields the following results; U1-V1 = 4 ohms, V1-W1 = 4 ohms, W1-U1 = 4 ohms. What is the value of continuity resistance for each winding ie. U1-U2?

Correct answer:

6 ohms.

Your Answer:

4 ohms.
15

Which of the following functions does the diode shown here perform?

Your answer is correct:

Return inductive current to supply at switch off.
16

Which of the following is an application of an capacitive sensor?

Correct answer:

Barometer.

Your Answer:

Proximity sensor.
17

Some ships generate electrical power at 440 Volts, but then step up this voltage to supply specific electrical equipment. One common example, may be to feed a large bow thruster. Why is this done?

Your answer is correct:

A large bow thruster will draw very large currents at low voltage. Being typically remote from the generator, significant voltage drops would occur at low voltage.
18

In an automatic temperature control system, operating with a PID controller which of the following settings or parameter adjustments may result in system oscillation?

Correct answer:

Gain too high.

Your Answer:

Too short D-time.
19

What are the main elements for Process Control?

Correct answer:

Process, Sensor, Final control element and Controller.

Your Answer:

Sensor, Modulation, Controller, Process.
20

Following shows circuitry of a peak detector. What is the output voltage curve, Vo if Vi is a sinusoidal input curve?

Correct answer:

Vo will be the same sinusoidal curve but at a lesser amplitude.

Your Answer:

Vo will peak when Vi is at the maximum, remain constant and fall to zero when Vi becomes negative.
21

When selecting switchgear to work with High Voltage it is important to use an appropriate arc quenching medium. What is meant by arc quenching medium?

Your answer is correct:

The gas, liquid or vapour which will minimise creation of an electric arc as contacts open.
22

A 250 V contactor has been fitted to a 220 V supply. Which of the following symptoms might be observed?

Your answer is correct:

Contactor chattering (vibrating).
23

The circuit shows a transformer with two windings, N (1) = 2 000 and N (2) = 1 000 turns, on a common magnetic circuit. Assume that there are no energy losses in the transformer itself. Calculate the output voltage V (2) when the input voltage is V (1) = 100 Volt.

Your answer is correct:

V (2) = 50 V.
24

This circuit consists of a current source I, a change-over switch S, a resistor R and a capacitor C. The current/time figures 1 to 4 show possible changes in the current I when the switch S is suddenly shifted from position 1 to 2 at time t = 0. Which diagram is correct?

Your answer is correct:

Figure A.
25

Which cell voltage is required to trickle charge a lead acid battery?

Correct answer:

2,15 V.

Your Answer:

2,5 V.
26

When the cable length exceeds approx. 10 meters we normally have to in case of a Pt 100, in some way compensate for the cable resistance. Do we also have to do this if we choose to use a T802 temperature sensor?

Your answer is correct:

No.
27

High Voltage systems rely on the installed protective equipment being able to interrupt any fault in the system. Throughout the system, the fault level has been calculated, and under no circumstances must the system be modified to exceed this fault level. What is meant by fault level?

Correct answer:

The amount of apparent power, that would be drawn from the generating plant, when a short circuit occurs at the bus bars.

Your Answer:

The current level flowing into a symmetrical short circuit fault between all three phases.
28

The continuity resistance of a 100 m long × 25 sq. mm cable (rated at 100 A) is to be checked. Which of the following results would you anticipate?

Correct answer:

Between 0,1 and 1,0 Ohm.

Your Answer:

Greater than 1 M Ohms.
29

When starting three phase induction motors which of the following starting methods will immediately apply rated voltage to the machine?

Your answer is correct:

Direct on Line.
30

Continuity testing of a delta connected three phase induction motor yields the following results; U-V = 3 Ohms, V-W = 3 Ohms, W-U = 6 Ohms. Which of the following is the likely condition?

Correct answer:

Short circuit winding between W and U.

Your Answer:

Open circuit winding between W and U.
31

What is the advantage of a transmitter with a narrow measurement range?

Your answer is correct:

Better linearity and increased accuracy.
32

How can a lead-acid type battery be checked to confirm if it is fully charged or not?

Your answer is correct:

Measure the relative density (specific gravity) of the electrolyte.
33

When polarity of the incoming power line is reversed, what happens to the DC motor?

Your answer is correct:

Motor rotates in the reverse direction.
34

This circuit consists of a voltage source V, a change-over switch S, a resistor R and a capacitor C. The voltage/time figures 1 to 4 show changes in the voltage V(C) when the switch S is suddenly shifted from position 1 to 2 at time t = 0. Only one of the diagrams is correct. Which?

Your answer is correct:

Figure 1.
35

This figure shows a transformer, with two windings, N(1) = 2 000 and N(2) = 1 000 turns, on a common magnetic circuit. Assume that there is no energy loss in the transformer itself. Calculate the current l(2) when the current l(1) = 2 A.

Correct answer:

l(2) = 2 A.

Your Answer:

l(2) = 4 A.
36

What should be the healthy continuity resistance of a 220 V, 2,2 kW, 10 A heating element, when checked near to it’s rated operating temperature?

Your answer is correct:

22 Ohms.
37

Which electronic component or system is this graphical symbol illustrating?

Your answer is correct:

Bandpass filter.
38

Can a ZENER BARRIER be installed in a hazardous area?

Your answer is correct:

No, as only the output from the barrier is intrinsically safe this is not allowed.
39

When there is a need to interrupt current flow in a high voltage system it may be very difficult to quench the electrical arc which is generated at the circuit breaker contacts. Which of the following arcing media is commonly found in high voltage marine switchgear?

Your answer is correct:

Vacuum.
40

The circuit shows a full-wave bridge rectifier. Which electronic component should be connected between “a” and “b” in order to obtain reduced ripple voltage to the load RL.

Your answer is correct:

Capacitor.
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