(3)
PR regulator
(4)
Metering valve
(5)
Dual resolver
(6)
Windmill bypass valve
(7)
Sequence valve
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PD METERED FLOWTORQUE MOTOR
PD PF BYPASSSHUT0FFPR
RETURNSOLENOIDFLAPPERVALVE
TO PUMP
OVERSPEEDPM
METERED
FLOW
CUTBACK
PD P1SOLENOID PF PD PD FUEL INLETFROM PUMP
PF
PF
SERVO
FILTER
PD WINDMILL BYPASS VALVE
P2 PF PRESSUREPM START AND
REGULATINGSEQUENCESHUTOFF
VALVE VALVE SOLENOIDP2 PD P1 MIN PRESSURE ANDPR
SHUTOFF VALVETO VALVES
PFMETERED FLOWANDTO FUELACTUATORS
DISTRIBUTIONVALVE PD
PD
PR REGULATOR
PR
METERING
DUAL RESOLVERVALVE
FUEL METERING UNIT PD - BYPASS (INTERSTAGE) PRESSUREPRESSURIZED FUEL FLOW
PF - FILTERED SERVO PRESSUREPRESSURIZED METERED FUEL FLOW
PR - REGULATED FILTERED SERVO PRESSURE
P1 - METERING VALVE INLET PRESSUREP2 - METERING VALVE OUTLET PRESSURE
BYPASS FUEL FLOW
MODULATED FUEL FLOW PM - MODULATED PRESSURE
Fuel Metering Unit Flow Schematic
Figure 3
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////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
(8)
Minimum pressure and shutoff valve
(9)
Start and run solenoid
(10)
Shutoff solenoid
(11)
Overspeed cutback solenoid
(12)
Torque motor
(13)
Flapper valve
4. EEC Alternator (N2 Transducer) (Fig. 1)
______________________________
A. The EEC alternator is the power source for the EEC and supplies a signal for the N2 rotor speed for airplane speed sensing.
B. The EEC alternator is attached to the aft face of the main gearbox at the 6 o'clock position. It includes a stator assembly and rotor.
C. The N2 rotor contains 12 different permanent magnets and is installed directly to a gearbox output shaft. The N2 rotor turns at speeds no more than 37,000 rpm (3.52 times N2 speed).
D. The stator assembly supplies two identical and independent 30 volt ac power outputs for each channel of the EEC. The stator contains a seperate winding to supply an N2 voltage signal to the N2 speed card. Fan air is supplied to the stator by a flexible hose to decrease the temperature of the stator (AMM 75-23-00/001).
5. EEC Speed Transducer (N1) (Fig. 1)
_________________________
A. The EEC speed transducer is an inductive N1 speed signal transmitter. It supplies two identical and independent signals to the EEC.
B. The EEC speed transducer is installed on the engine intermediate case at approximately the 5 o'clock position.
C. The EEC speed transducer includes a permanent magnet, two electrically independent wire pickup coils, two ferromagnetic coil cores, and a non-magnetic support tube and mounting flange.
D. The dual pickup coils are in the point of the EEC speed transducer installed at the end of the shaft. The EEC speed transducer is installed into the intermediate case, and the point near 60 teeth machined in the N1 rotor shaft.
6. EEC Inlet Total Pressure/Temperature (PT2/TT2) Probe (Fig. 1)
____________________________________________________
A. The PT2/TT2 probe measures the total pressure and temperature of the air which goes into the engine. The PT2/TT2 probe is installed to the inlet cowl and extends into the inlet air stream at the 1 o'clock position.
B. The PT2/TT2 probe is of a welded and brazed construction and includes the non-removable parts that follow:
(1)
Housing
(2)
Two platinum temperature sensing resistance elements
(3)
Connector adapter
(4)
Two electrical receptacles
(5) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 发动机燃油和控制 1(101)
