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Electromagnetic brake to lock the actuator when the brake is de-energized
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Pseudo-tachometer (derived rate feedback) to supply speed rate feedback signals to the servo loop internal to the actuator
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Actuator position RVDT.
The rudder trim actuator position RVDT sends position signals to the L1 ACE for servo-loop control. The L1 ACE provides rudder trim position to the PFCs for fault monitor. These signals also go to the AIMS cabinets which control the rudder trim position indicator.
EFFECTIVITY BEJ ALL 27-21-00
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RUDDER CONTROL -FUNCTIONAL DESCRIPTION -RUDDER TRIM
Rudder Trim Position Transducer
The rudder trim position transducer sends a position signal to the R ACE, which sends the signal to the PFCs. The PFCs monitor this signal and compare it to the rudder trim actuator position RVDT for fault monitor.
Normal and Secondary Mode Control
During normal and secondary modes of operation of the PFCS, the PFCs control the rudder trim actuator through the L1 and R ACEs.
When the pilot turns the rudder trim selector, command signals from the 15 degree switch contacts go to the rudder trim actuator arm status function and then to the R ACE and on to the PFCs.
When the pilot turns the rudder trim selector to close the 25 degree contacts, a discrete signal goes through the L1 ACE to the PFCs. The PFCs send an engage command through the ACEs to the rudder trim actuator where the electromagnetic brake is released. The brake status goes from the actuator through the R ACE to the PFCs. After they recieve the brake released status, the PFCs send a slow rate command to the actuator through the L1 ACE servo command function. The PFCs and ACEs cause the rudder trim actuator to move at a rate of 0.38 units per second.
EFFECTIVITY
BEJ ALL
When the pilot turns the rudder trim selector to close the 40 degree contacts, a discrete goes to the PFCs through the R ACE to command high rate rudder trim. The PFCs send that signal through the L1 ACE servo command function that causes the rudder trim actuator to move at 1.54 units per second.
When the manual trim cancel switch is closed, a discrete signal goes through the L1 ACE To the PFCs. The PFCs send an engage command through the ACEs and when the actuator brake is released, the PFCs send a command to operate the actuator motor at high speed (1.54 units per second).
In normal mode, when TAC is active, the PFCs and the L1 and R ACEs cause the rudder trim actuator to move at a rate as much as 8 units per second.
The signal from the rudder trim actuator position RVDT closes the servo loop in the L1 ACE.
The pseudo-tachometer (derived rate) supplies rate feedback to the speed control in the rudder trim actuator.
On the ground, the PFCs limit the rudder trim actuator movement to 17 units of rudder trim. In flight, the PFCs let the trim actuator move to its mechanical stops. This causes a maximum of 18 units of rudder trim at low airspeed. Because the rudder trim indicator limit is 17 units, the indicator shows 17 units for a trim condition of 17 units or more.
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RUDDER CONTROL -FUNCTIONAL DESCRIPTION -RUDDER TRIM
The PFCs compare the signal from the rudder trim actuator RVDT with the signals from the rudder trim position transducer. If the signals do not agree, the PFCs stop the operation of the rudder trim. The PFCs also compare the signal from the rudder trim actuator RVDT with the PFC commanded position. If these signals do not agree, the PFCs stop the operation of the rudder trim.
If the R ACE does not operate, automatic trim by the TAC function does not operate. The pilot can control manual trim with the rudder trim selector. The PFCs then control the rudder trim actuator through the L1 ACE. In this condition, the rudder trim operates at 0.38 units per second. The 40 degree selector position and the manual trim cancel switch do not operate.
If the L1 ACE does not operate, the PFCs stop the operation of the rudder trim.
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本文链接地址：777 AMM 飞机维护手册 飞行操纵 Flight Controls 1(60)
