(a) Observe BATT light on M238 illuminates.
D. Test standby power off/master caution time delay.
(1)
Open GEN DRIVE OIL NO. 1 and NO. 2 LOW PRESS circuit breakers on P6-4.
(2)
Close BAT BUS CONT AUTO and BAT BUS circuit breakers on P6-5.
(3)
Press MASTER CAUTION light to extinguish.
(4)
Set STANDBY POWER switch to OFF.
(a) Observe STANDBY PWR OFF light illuminates and approximately one second later the MASTER CAUTION light illuminates.
E. Restore system to normal.
(1)
Close BAT BUS CONT AUTO and BAT BUS circuit breakers on P6-5 and GEN DRIVE OIL NO. 1 and NO. 2 LOW PRESS circuit breakers on P6-4.
(2)
Set STANDBY POWER switch to AUTO.
(3)
Remove external power if no longer required (Ref. 24-22-0 MP).
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4. Standby Power System - Operational Test
A. Set BATT switch to ON.
B. Set DC meter selector switch to the following and check that DC voltmeter reads:
(1)
Zero at TR3 position
(2)
Greater than 22 volts at BAT position
(3)
The same as at BAT position (or within 1/2 volt less) when at BAT BUS position
C. Set GROUND POWER switch to ON.
D. Set DC meter selector switch to the following and check that DC voltmeter reads:
(1)
26 + 4 volts dc at TR3 position
(2)
The same as at TR3 position (or within 1/2 volt less) when at BAT BUS position
E. Set STANDBY POWER switch to OFF and check that STANDBY PWR OFF light illuminates.
F. Set AC meter selector switch to STBY PWR and check that AC voltmeter reads zero.
G. Set STANDBY POWER switch to AUTO with DC meter selector switch still at BAT BUS position, and check that:
(1)
STANDBY PWR OFF light extinguishes
(2)
DC voltmeter reads 26 + 4 volts
(3)
AC voltmeter reads 115 + 5 volts
(4)
Frequency meter reads 400 + 10 Hz
H. Set GROUND POWER switch to OFF and check that:
(1)
STANDBY PWR OFF light stays extinguished
(2)
DC voltmeter reads 26 + 4 volts
(3)
AC voltmeter reads 115 + 5 volts
I. Deleted
J. Deleted
K. Set STANDBY POWER switch to AUTO and check that STANDBY PWR OFF light remains extinguished.
L. Deleted
M. Set DC meter selector switch to TR3 and check that DC voltmeter reads zero.
N. Return standby power system to normal.
(1)
Remove electrical power if no longer required (Ref. 24-22-0).
(2)
Set BATT switch to OFF.
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Oct 20/86 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 24-54-1 Page 503
STANDBY POWER SYSTEM - DESCRIPTION AND OPERATION
EFFECTIVITY
AL ALL EXCEPT N310AU thru N329AU; N310AU thru N329AU after incorporation of SB 24-1040
DL ALL EXCEPT N301DL thru N330DL; N301DL thru N330DL after incorporation of SB 24-1040
NZ ALL EXCEPT ZK-NAP thru ZK-NAS, ZK-NQC; ZK-NQC after incorporation of SB 24-1040
YB ALL EXCEPT 9H-ABA thru 9H-ABC; 9H-ABA thru 9H-ABC after incorporation of SB-1040
1. General
A. The standby system is used to supply power to essential ac and dc systems. Under normal conditions in flight, the standby power switch is in the AUTO position, the standby ac bus is energized from the 115-volt A transfer bus No. 1, and the standby dc bus is energized from dc bus No. 1. In the event of losing either the ac or dc normal power, the auto standby power relay (R37) is deactivated, connecting the dc standby bus to the battery bus and the ac standby bus to the static inverter (Fig. 1).
B. During checkout of the system on the ground, or refueling the airplane on battery power only, the standby system is activated by placing the standby power switch in the BAT position. This activates the manual standby power relay (R328), which connects the dc standby bus to the battery bus and the ac standby bus to the static inverter.
C. During electrical smoke isolation procedures, the standby system is deactivated by placing the standby power switch in the OFF position.
2. Operation
A. The ac standby power bus is a single-phase, 115-volt ac power source, which is used to supply 400-Hz power to essential ac systems (Fig. 1). A static inverter, energized by 28 volts dc from the storage battery through the battery bus, is the alternate source of single-phase, 400-Hz, 115-volt power to the ac standby bus. The power is used for essential communication and navigation equipment, so that the pilot's essential flight instruments will not be deactivated in the event all 400-Hz generated power becomes unavailable during flight. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737 AMM 飞机维护手册 电源 ELECTRICAL POWER(71)
