........................................................................ | APU GEN | 2 | | POWER SYSTEM | | ........................................................................ | OK | 2 | ........................................................................ | LAST FLT ( ) | 15 | | END OF DATA | | | *[2] | | ........................................................................ | FOR PREVIOUS | 15 | | FLT PUSH NOW | | | *[3] | | 2.............................…........................................1 *[1] The error code refer to the failure in the GCU, causing the trip. *[2] The number in the parenthesis indicates the flight cycle just
viewed. The most recent cycle is identified (00), the cycle
before (01), two cycles before (02). The earliest flight cycle
that can be viewed is (07). *[3] If BIT is pushed, one earlier flight cycle is displayed. If BIT
is not pushed, display sequence ends.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
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A
757
MAINTENANCE MANUAL
(5)
The PERIODIC TEST pushbutton starts the maintenance test. The BPCU display shows the four power channels and any errors detected on them. If no defects are found, the display indicates "OK". The PERIODIC TEST should be performed with only battery power applied to the plane (No AC power. When AC power is applied, the BPCU fails to interrogate the circuits actively involved in normal monitoring. The results of the periodic test under these conditions will be inconclusive). The maintenance test should only be performed during major airplane maintenance, not during routine checks.
(6)
The time that each BITE message appears on the BPCU display can be cut by repressing the button that started the display sequence. Thus if BIT is initially pushed, pressing BIT during a particular message will advance the display sequence to the next message. In this way, the display sequence can be speeded up.
(7)
The current flight cycle plus seven previous flight cycles are saved in eight memory locations. The RESET pushbutton makes previous flight BITE information inaccessible.
(8)
A BPCU flight cycle is defined as follows: With both engines initially shut off, the cycle starts with the first engine start. The cycle must then include an ground-air-ground cycle. The cycle continues after both engines are shut down. A new cycle starts with the next engine start.
(9)
When BIT or PERIODIC TEST is pushed on the BPCU, all BITE information stored for the latest flight cycle appears on the BPCU display. If two identical messages are stored in BITE memory, the same BITE message will be displayed twice. BITE does not disregard a message, even if it was already displayed during a flight cycle. A situation which can induce identical BITE messages occurs when the airplane is on the ground, and the BPCU's power is switched on and off. When BPCU power is first applied, any detected fault causes a BITE message to be stored in memory. Upon removal of BPCU power, the BITE message remains in memory. If BPCU power is again applied and the fault condition remains, a second identical BITE message will be stored in memory, during the same flight cycle.
(10)
The BITE system does not cover the following areas: 1) Standby and dc power systems; 2) electrical power flight compartment lights (ac and dc), and, 3) electrical power flight compartment instruments (ac and dc).
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A
757 FAULT ISOLATION/MAINT MANUAL
AC POWER FAULT SENSING
COMPONENT SHT 102 FIG. QTY ACCESS/AREA REFERENCE
CIRCUIT BREAKERS - (REF 24-22-00, FIG. 101) AUX POWER, C905 LEFT BUS TIE, C902 LEFT GENERATOR, C901 RIGHT GENERATOR, C903 INTEGRATED DRIVE, M10160 RIGHT BUS TIE, C904 AUXILIARY POWER UNIT, M281 GENERATOR - (REF 24-11-00, FIG. 101) GENERATOR - (REF 24-21-00, FIG. 101)
CURRENT DIFFERENTIAL PROTECTION APU GENERATOR, T111TRANSFORMER - (REF 31-01-34, FIG. 101) 24-23-01
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本文链接地址：757 AMM 飞机维护手册 电源 ELECTRICAL POWER 1(96)
