*
N2
*
Broadband.
Broadband vibration is the total engine vibration.
The signal conditioner unit also does these functions:
*
Compares the N1 and N2 vibration levels to find which is highest
*
Keeps in memory the vibration data for the last six flight legs
*
Calculates engine balance solutions for the EBS.
All vibration data goes to the AIMS. Program pins on the signal conditioner unit identify the engine position, engine manufacturer, and engine model.
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ENGINE INDICATING -AVM -FUNCTIONAL DESCRIPTION
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ENGINE INDICATING -AVM -INDICATION
Secondary Engine Display
The secondary engine display shows the highest vibration level for each engine. The rotor identification is below the vibration data. If the N1 or N2 speed signal fails, the rotor identification shows broadband (BB) vibration.
If the vibration level is equal to or more than 4.0 scalar units, the vibration display automatically shows. Also, the display will show in reverse video format (black numbers on a white background).
When an engine is shut down, the related vibration data does not show.
Performance Maintenance Page
The performance maintenance page shows all the engine vibration data. The vibration data only shows for channel A of the AVM signal conditioner unit. The AVM signal conditioner unit does not use channel B.
If the N1 or N2 speed signal fails, only the broadband vibration data shows.
Training Information Point
At low engine speeds, the N1 vibration changes to dashes. This is because the broadband vibration is too large in proportion to the N1 vibration.
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PW4000 SERIES ENGINES
777 AIRCRAFT MAINTENANCE MANUAL
ENGINE INDICATING -AVM -INDICATION
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ENGINE INDICATING -AVM -ENGINE BALANCING SYSTEM (EBS)
General
The engine balancing system (EBS) lets you select which balance weights on the engine to change to decrease engine vibration.The AVM signal conditioner unit for each engine and the AIMS central maintenance computing function (CMCF) make up the EBS.
The AVM signal conditioner unit supplies the data for the engine balancing displays. You use the MAT to operate the EBS.
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本文链接地址：777 AMM 飞机维护手册 发动机指示 Engine Indicating PW 777 AIRCRAFT MAINTENANCE MANUAL(14)
