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1. As shown in the illustration, which of the listed types of motor controllers and starters is indicated?
EL-0012
A. Across-the-line
B. Capacitor
C. Autotransformer
D. Part-winding
1. Answer: C
2. 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
2. Answer: B
3. You are performing an out-of-circuit test on the semi-conductor shown in the illustration. Using an ohmmeter on 'low power' setting and with leads properly inserted, which of the listed results would indicate a good Emitter-Base junction?
EL-0068
A. A low reading with red lead on 'A' and black lead on 'C'; and a high reading with the leads reversed.
B. A low reading with red lead on 'A' and black lead on 'B'; and a high reading with the leads reversed.
C. A low reading with black lead on'A' and red lead on 'B'; and a high reading with the leads reversed.
D. A low reading with black lead on 'A' and red lead on 'C'; and a high reading with the leads reversed.
3. Answer: D
4. 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
4. Answer: A
5. On a vessel with turbo-electric drive, which of the following conditions would indicate that the propulsion motor had dropped out of synchronization with the propulsion generator?
A. Excessive vibration of the vessel
B. Tripped main motor interlocks
C. Overheated crosstie busses
D. Closed contact in the field circuits
5. Answer: A
6. On some diesel-electric ships, the DC propulsion motor will only attain half speed when the generator fields are fully excited. Speeds above this are obtained by _____________.
A. rotating brush alignment
B. raising the generator engine speed
C. lowering the generator engine speed
D. decreasing excitation
6. Answer: B
7. In a diesel electric plant, raising the generator's field excitation will cause the DC propulsion motor to ________.
A. increase in speed
B. decrease in speed
C. affect generator speed only
D. affect main motor speed if done in conjunction with higher generator engine speeds
7. Answer: A
8. Electric propulsion coupling excitation is reduced at slow speeds to ___________.
A. increase speed control
B. increase shaft torque
C. prevent coupling overheating
D. prevent coupling slippage
8. Answer: C
9. 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
9. Answer: A
10. 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
10. Answer: B
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