大学英语期末考试(A)

大学英语期末考试（A）

第一部分：单选题

1. The starting current of an a.c. motor is_____ the rated current.

A. the same as

B. much larger than

C. less than

D. equals

2. With a_____ load the voltage and current are in phase.

A. pure resistance

B. capacitive

C. inductive

D. None of the above

3. The emergency generator or emergency battery is connected to_____ on most large ships.

A. distribution boards

B. section boards

C. emergency switch boards

D. main switch boards

4. Switchboards may be of the dead-front type in which all live parts are installed behind_____ and only the operation handles and instruments are on the front.

A. the capstan

B. the collector

C. the panels

D. the surface

5. Remote control means that_____.

A. the system is manned manually

B. the system is situated remotely from the operator

C. the system is controlled automatically

D. all the above

6. The difference between measured and desired values is called_____.

A. make-up

B. desired value

C. deviation

D. set value

7. Prior to any overhaul work on electric equipment, it is important to ensure the circuits are_____.

A. live

B. dead

C. excited

D. on line

8. Before starting an engine by air ,the engine must _________

A. be turned by a turning gear for at least one minute

B. be turned by a turning gear for at least two minutes

C. be turned at least one complete turn

D. be turned at least two complete turns

9. Shore power must be_____ during dock repair.

A. disconnected

B. switched off

C. cut off

D. connected

10. The switchboards for a.c. systems differ from the d.c. switch gear in that the open type panels are generally_____ and the dead-front switch gear is the common rule.

A. permissibly

B. permissible

C. no permissible

D. not permissible

11. Current changing in direction and rising and falling in value is_____.

A. A.C.

B. D.

C. C. generator

D. fresh water generator

12. The separate supplies are connected in either star or delta formation. The star formation is most commonly used and requires_____ slip-rings on the alternator.

A. two

B. three

C. four

D. five

13. The difference between measured and desired values is called

A. offset

B. error

C. deviation

D. set value

14. After the trouble of the automatic control system has been completely eliminated, assistance is_____ required.

A. remained

B. still

C. no longer

D. much mere

15. The field coils_____ and the armature is_____. This is in fact the arrangement adopted for large, heavy duty alternators.

A. stationary/rotate

B. stationary/stationary

C. rotate/stationary

D. rotate/rotate

16. An a.c. switchboard is usually_____ the corresponding d.c. board because of the higher voltage and lower currents and smaller bus-bars.

A. larger and heavier than

B. as much as

C. smaller and lighter than

D. more dangerous than

17. In_____ the control action is independent on(of) the output.

A. a closed loop control system

B. an open loop control system

C. a boiler control system

D. a steering gear control system

18. It_____ for an emergency generator to require paralleling.

A. is usual

B. is not usual

C. is necessary

D. is not impossible

19. Which of the motors for the devices listed below is fitted with an instantaneous overload relay?

A. Fan

B. Pump

C. Winch

D. Machine tool

20. An electrical device which prevents an action from occurring until all other required conditions are met is called a/an_____.

A. limit

B. monitor

C. modulator

D. interlock

21. A circuit breaker and a fuse have a basic similarity in that they both_____.

A. can be reset to energize the circuit

B. should open the circuit when overloaded

C. will burn out when an over current flow develops

D. All of the above