曝光台 注意防骗
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5. The APU exhaust conducts the engine exhaust gas overboard and reduces
the noise level of the high velocity gas flow, the exhaust duct consists of a
heat shield and a muffler.
LESSON 19
AUXILIARY POWER UNIT (2)
VOCABULARY
1. primarily [ praimrili ] ad. 首先;主要是; 基本上
2. furnish [ f:ni ] vt. 供给;提供
3. teminal [ t:minl ] n. 接线端
4. neutral [nju:trl ] n. 中线
5. lead [ li:d ] n. 导线;引线
6. outside [ aut said ] prep. 在…外面
7. discharger [ dista:d ] n. 排气装置;放电器
8. slotted [ sl tid ] a. 有槽的,开缝的
9. stud [ std ] n. 双头螺栓;柱螺栓
10. frequency [fri:kwnsi ] n. 频率
11. achieve [ ti:v ] vt. 达到(目的); 实现;得到
12. breaker [breik ] n. 跳开关;断路器
13. closing [kluzi ] n. 闭合;接通(电路)
14. tripping [tripi ] n. 松开;断开(电路)
15. permanent magnet [p:mnnt ] [mægnit ] 永久磁铁
16. assist [ sist ] v. ; n. 帮助;参与
17. latch [ læt ] n. 锁定
18. spring [ spri ] n. 弹簧
19. hold [ hould ] v. 保持
20. contact [ 'k ntækt ] n. 触点;触头
21. contactor [ k ntækt ] n. 接触器
22. signal [signl ] n. 信号
23. gain [ gein ] v. 获得;达到
24. application [ æplikein ] n. 应用;施加
25. allow [ lau ] v. 允许;使…能
26. momentary [moumntri ] a. 瞬时的;短暂的
27. energize [end aiz ] v. 通电;供能
28. coil [ k il ] n. 线圈
29. polarity [ poulæriti ] n. 极性
30. receptacle [ riseptkl ] n. 插座
31. bus protection panel ( BPP ) 汇流条防护板
32. charger [ta:d ] n. 充电机
33. essential [ i senl ] a. 主要的;必要的
34. absence [æbsns ] n. 缺席;没有;不存在
TEXT
[1] The APU driven generator is mounted on the forward face of the APU accessory
drive gearbox. The APU generator produces the AC power required by the airplane
systems primarily for ground operation, the generator can also be used as a backup
generator in flight. APU is used to furnish 60 KVA of electrical power on the
ground and used as AC power source of 50 KVA in flight .
Fig. 19-1 APU ac generator
[2] The APU ac generator has 6 ac terminals:
T1,T2, and T3 are the power terminals, T4, T5 and T6 are the neutral or
ground terminals.
T1 and T4 are for phase A, the leads are color-coded red.
T2 and T5 are for phase C, the leads are color-coded blue.
T3 and T6 are for phase B, the leads are color-coded yellow.
These terminal numbering and color-coding is the same as for the engine-driven
generators. Cooling air enters through a duct from outside the APU compartment,
passes through the generator and discharges into the APU. The generator is attached
to the APU accessory drive gearbox with 12 slotted holes over mounting studs. The
neutral current transformer sense the total current flowing through the APU
generator at the neutral terminal.
[3] The ac power produced by APU generator is of constant frequency. To achieve
this, the APU generator drive (including a gearbox) can be used for reducing the
high speed of the APU engine to a lower speed. The APU engine drive the generator
in lower speed to produce ac power at constant frequency.
[4] The two APU generator breakers (see figure 19-2) connect 115 volt ac, 400
Hertz, 3-phase power to the distribution system from the APU generator. The APU
generator breakers are located in the bottom of the p6 panel in the flight
compartment. The breaker has a dc coil for closing and tripping. A permanent
magnet assists closing and latches the breaker in the closed position. An internal
spring assists opening and holds it in the open position. The breaker has 6 main 115
volt ac contacts and 20 auxiliary contacts. The auxiliary contacts are used to control
the positions of APU generator breakers and external power contactors, and for
indicating lights in the flight compartment. The closing and tripping signals for the
breakers are from the P5-4 panel. The breaker contacts position is indicated by the
blue APU GEN OFF BUS light on the P5-4 panel. Access to the breaker is gained
by opening circuit breaker panels P6-11 and P6-12 at the bottom of P6 panel.
Fig 19-2 APU generator breaker
[5] Application of 28 volt dc to close, allows momentary energizing of the
coil .When the breaker closes, the coil deenergizes through the auxiliary contact and
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航空工程英语基础（中英文对照）(26)
