Purpose
The EGT thermocouple probes supply a signal for exhaust gas temperature to the EEC.
The EGT (T4.95) thermocouple probes make analog electrical signals in proportion to EGT. The signals go through the EGT harness to the EEC for indicating and start limit protection during autostart.
Location
There are four probes on the turbine exhaust case; two are on each side of the engine. You install the probes into the EPR probes.
Physical Description
Each probe has two sets of thermocouples. One set is for each channel of the EEC.
The EGT thermocouple harness is one piece. It connects the EGT probes together.
Training Information Point
Spring clips hold the EGT harness to the turbine case. The clips make it easier to remove and install the harness.
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ENGINE INDICATING -EGT -EGT (T4.95) THERMOCOUPLE PROBES AND HARNESS

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PW4000 SERIES ENGINES

777 AIRCRAFT MAINTENANCE MANUAL

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ENGINE INDICATING -AVM -GENERAL DESCRIPTION

Purpose
The airborne vibration monitoring (AVM) system monitors and records the engine vibration levels.
General Description
There is one AVM system for each engine. Each AVM system has these components:
*
Accelerometer (3)

*
Remote charge converter (RCC)

*
AVM signal conditioner unit.

The accelerometers send signals that are proportional to the engine vibration. Each accelerometer signal goes to the RCC for signal conversion and amplification. The RCC sends amplified vibration signals to the AVM signal conditioner unit.
The AVM signal conditioner unit uses these vibration signals and the N1 and N2 speed signals to calculate the vibration levels for each rotor. The signal conditioner unit sends the vibration data to the AIMS. The AIMS shows the vibration data on the primary display system.
The signal conditioner unit also keeps in memory the vibration data for use with the engine balancing system (EBS). The EBS is a function of the signal conditioner unit and the AIMS. You get access to it through the MAT.
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ENGINE INDICATING -AVM -GENERAL DESCRIPTION

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ENGINE INDICATING -AVM -ACCELEROMETERS AND REMOTE CHARGE CONVERTER

Accelerometers
The accelerometers use piezoelectric crystals to get input for engine vibration and send it to the remote charge converter (RCC).
　
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