(2)
Provide external power to the airplane and check that the following lights are on.
(a)
EXTERNAL POWER CONN light on external power panel P19.
(b)
GRD POWER AVAILABLE light on overhead panel P5-4.
(c)
EXT PWR TR light on M238.
(d)
EXTERNAL POWER NOT IN USE light on external power panel P19.
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C. Test No. 3 TR Unit Circuit
NOTE: To obtain an indication from the M238 module, place IND-TEST switch (S2) in IND position.
(1)
Close BAT BUS (C20), DC BUS INDICATION TR NO 3 (C25), BAT TRANS CONT (C167), and FUELING & EXT PWR CONT (C32) circuit breakers on panel P6-5.
(2)
Check that NO 1 TRANS CONT (C464), NO 2 TRANS CONT (C465), and TR UNITS NO 3 (C808) circuit breakers on panel P6-4 are closed; check that NO 2 GEN BUS MAIN DISTRIBUTION (C817) circuit breaker on panel P6-12 is closed.
(3)
Set BAT switch to ON.
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(4)
Set GRD PWR switch to ON. Check that EXTERNAL POWER NOT IN USE light on external power panel P19 goes off and TR3 light on M238 comes on.
(5)
Check that BATT light on M238 is on.
(6)
Check that dc voltmeter indicates 26 + 4 volts when meters selector switch is set to TR 3 and BAT BUS.
(7)
Open HOT BAT BUS (C22) circuit breaker on panel P6-6. Check that dc voltmeter reads 26 + 4 volts when selector switch is set to BAT BUS and zero when set to BAT.
(8)
Set BAT switch to OFF. Check that BATT light on M238 goes off and dc voltmeter reads zero when selector switch is set to BAT and BAT BUS.
(9)
Open TR UNITS NO 3 (C808) circuit breaker and check that TR3 light on M238 goes out.
(10)
Set BAT switch to ON. Set meters selector switch to TR 3 and check that voltmeter reads 0-1 volt.
D. Test No. 1 and 2 TR Units Circuits and Control
NOTE: To obtain an indication from the M238 module, place IND-TEST switch (S2) in IND position.
(1)
Check that the following circuit breakers are closed:
(a)
CONTROL GENERATOR NO 1 (C4), CONTROL GENERATOR NO 2 (C5), CONTROL GENERATOR APU (C6), TR UNITS NO 1 (C806), and TR UNITS NO 2 (C807) on P6-4.
(b)
DC BUS POWER NO 1 (C31) and DC BUS INDICATION BUS NO 1 (C23) on P6-5.
(c)
HOT BAT BUS (C22) on P6-6.
(d)
TRANSFER BUS NO 1 NORMAL (C819) and NO 2 ALT (C822) on P6-11.
(e)
TRANSFER BUS NO 2 NORMAL (C821) on P6-12.
(2)
Check that NO. 1 light on M238 is on.
(3)
Set dc selector switch to TR 1.
(a)
Check that voltmeter indicates 26 + 4 volts.
(b)
Check that ammeter indicates load is present.
(c)
Check that NO 2 and TR3 lights on M238 do not come on.
(4)
Close DC BUS POWER NO 2 (C27) and DC BUS INDICATION BUS NO 2 (C24) circuit breakers. On M238, check that NO 2 light illuminates and TR3 light does not come on.
(5)
Open TR UNITS NO 1 (C806) circuit breaker and check that NO 1 light goes out and that the voltmeter and ammeter read zero.
(6)
Check that TR UNITS NO 2 (C807) circuit breaker on P6-4 and TRANSFER BUS NO 2 NORMAL (C821) circuit breaker on P6-12 are closed. Check the following:
(a)
NO 1 light on M238 remains out.
(b)
Voltmeter indicates zero (selector switch set to TR 1).
(c)
NO 2 light on M238 illuminates.
(7)
Set dc meters selector switch to TR 2.
(a)
Check that the voltmeter indicates 26 + 4 volts.
(b)
Check that the ammeter indicates a load is present.
(8)
Open TR UNITS NO 2 (C807) circuit breaker on P6-4.
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(a) Check that NO 2 light on M238 goes off and the voltmeter reads zero.
E. Test No. 3 TR Unit/Battery Bus Transfer Circuits and Control
NOTE: To obtain an indication from the M238 module, place IND-TEST switch (S2) in IND position.
(1)
Check that BUS TRANSFER switch is set to AUTO.
(2) 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(53)
