11 August 2016

ELECTRICAL QUESTIONS AND ANSWERS-MCQ-ETO


QUESTIONS AND ANSWERS FOR ETO
             
1. The full torque electric brake on an electric cargo winch functions to _____________.          
A. act as a backup brake in the event the mechanical brake should fail  
B. automatically hold the load as soon as current to the  machine is shut off       
C. automatically govern the lowering speed of the load             
D. automatically govern the hoisting speed of the load               
Ans : B

2. When troubleshooting most electronic circuits, "loading  effect" can be minimized by using a voltmeter with a/an  ___________________. 
A. input impedance much greater than the impedance across  which the voltage is being measured
B. input impedance much less than the impedance across   which the voltage is being measured
C. sensitivity of less than 1000 ohms/volt  
D.sensitivity of more than 1000 volts/ohm
Ans : A  

3. An electric tachometer receives the engine speed signal from a _______________.              
A. small generator mounted on the engine
B. bimetallic sensing device           
C. stroboscopic sensing device      
D. vibrating reed meter generating a voltage proportionate to engine speed
Ans : A

4. A three-phase alternator is operating at 450 volts with  the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter reading would increase by _____               
A. 17.8 KW          
B. 23.2 KW          
C. 30.6 KW          
D. 37.8 KW          
Ans : B  

5. A semiconductor that decreases in resistance with an  increase in temperature is known as a _____________.           
A. resistor           
B. thermistor      
C. diode
D. thermopile     
Ans : B

6. The shunt used in an ammeter should be connected in  ____________.      
A. series with the load and in parallel with the meter movement       
B. parallel with the load and in series with the meter movement       
C. parallel with the load and in parallel with the meter  movement   
D. series with the load and in series with the meter movement         
Ans : A

7. Brushless generators are designed to operate without the use of ___________.    
A. brushes           
B. slip rings         
C. commutators
D. all of the above             
Ans : D

8. An operating characteristic appearing on the name plates of shipboard AC motors is _____________.
A. the type of winding      
B. input kilowatts              
C. temperature rise          
D. locked rotor torque     
Ans : C

9. Low horsepower, polyphase, induction motors can be started with full voltage by means of _____________.
A. compensator starters 
B. autotransformer starters          
C. across-the-line starters              
D. primary-resistor starters           
Ans : C

10. Moisture damage, as a result of condensation occurring  inside of the cargo winch master switches, can be reducedby __________________.    
A. installing a light bulb in the pedestal stand           
B. coating the switch box internals with epoxy sealer            
C. venting the switch box regularly              
D. using strip heaters inside the switch box
Ans: D

11. Which of the following conditions will occur if thesolenoid coil burns out on a cargo winch with an electricalbrake?    
A. The brake will be set by spring force.     
B. The motor will overspeed and burn up.  
C. The load suspended from the cargo boom will fall.             
D. Nothing will happen; the winch will continue to operate as usual.
Ans : A

12. 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?       
A. Normal charging circuit              
B. Quick charging circuit  
C. Trickle charging circuit
D. High ampere charging circuit   
Ans : C

13. A ground can be defined as an electrical connection between the wiring of a motor and its ____________. 
A. shunt field      
B. circuit breaker               
C. metal framework         
D. interpole         
Ans : C

14. External shunts are sometimes used with ammeters to_______.               
A. increase meter sensitivity         
B. permit shunts with larger resistances to be utilized          
C. prevent damage to the meter movement from heat generated by the shunt            
D. enable the construction of a compact meter with a virtually unlimited range            
Ans : C

15. The output voltage of a 440 volt, 60 hertz, AC generator is controlled by the _____________.         
A. prime mover speed      
B. exciter output voltage
C. load on the alternator 
D. number of poles           
Ans : B

16. Any electric motor can be constructed to be _____________.     
A. short proof     
B. ground proof  
C. explosion proof
D. overload proof              
Ans : C  

17. Which of the following statements represents the main  difference between a relay and a contactor?
A. Contactors control current and relays control voltage.     
B. A relay is series connected and a contactor is parallel  connected.               
C. Contactors can handle heavier loads than relays.              
D. Contactors are made from silver and relays are made from copper.            
Ans : C

18. Which of the following statements is true concerning a  polyphase synchronous propulsion motor?
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.
Ans : A

19. Where a thermal-acting breaker is required to be used in anarea 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               
Ans: C   

20. Which of the following statements represents an application of a silicon controlled rectifier?           
A.To provide DC power for a main propulsion motor.             
B. For use as a voltage reference diode.     
C. For sensing flame in an automated burner.          
D.To eliminate power supply hum.               
Ans : A

21. The electrolyte used in a nickel-cadmium battery is  distilled water and ______________. 
A. diluted sulfuric acid      
B. potassium hydroxide   
C. lead sulfate    
D. zinc oxide       
Ans : B

22. Which of the damages listed can occur to the components of a winch master control switch, if the cover gasket becomes deteriorated?     
A. Overheating of the winch motor.             
B. Contamination of lube oil.          
C. Sparking at the winch motor brushes.    
D. Rapid corrosion of switch components. 
Ans : D

23. An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an ____________.        
A. open circuit    
B. short circuit   
C. polarized ground          
D. ground reference point              
Ans : B

24. A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with _____________. 
A. both meters in series with the resistance             
B. both meters in parallel with the resistance          
C. the ammeter in series and the voltmeter in parallel with the resistance     
D. the ammeter in parallel and the voltmeter in series with the resistance    
Ans : C

25. In general, polyphase induction motors can be started on full line voltage by means of ______________.     
A. compensator starters 
B. autotransformer starters          
C. across-the-line starters              
D. primary-resistor starters           
Ans : C

 "If you can't explain it simply, you don't understand it well enough." --Albert Einstein

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ELECTRICAL QUESTIONS AND ANSWERS-MCQ-ETO
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