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Fav 900
Transmission / Transmission control unit
Transmission control unit functional sequence
A
General
Fav 900 chassis number 23/3001 and up
6.8.2001
1005
000005
A
a
3/4
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Transmission control unit functional sequence
The A009 - actuator unit controls the actuator shaft, thereby changing the transmission ratio in the
ML transmission.
The actuator unit comprises:
ETNum-list
Once the ignition is on, the actuator unit locates the reference point (approximate neutral point between
forward and reverse travel).
When the engine has started, the actuator unit locates the reference point (exact neutral point between
forward and reverse travel).
Automatic maximum output control (restricting the reduction in engine speed or adaptation to the
engine output)
Example: the engine speed is reduced when a load is applied. The electronics change the transmission
ratio towards slow so that the engine speed is not reduced too far.
Automatic maximum output control is always engaged once the engine is started. However, the
reduction in engine speed can be changed from 0 to 30% (see Operating Manual).
The default setting is 14%.
Automatic maximum output control functions:
The electronics detect the setpoint engine speed from the position of the accelerator pedal by means of
the analogue position sensor (potentiometer) on the accelerator.
Control - setpoint transmission ratio has been reached.
The tractor is put under load, and the engine speed drops.
The automatic maximum output control only ever changes the transmission ratio towards slow.
The automatic maximum output control is engaged at:
reduction in engine speed of over 180 rpm + set value.
Text-module
This means that the automatic maximum output control changes the transmission ratio towards "Slow"
from 1620 rpm. Theoretically the automatic maximum output control changes the transmission ratio
when under load until the travel speed reaches 0.
Note:
Since the automatic maximum output control only changes the transmission ratio towards slow,
it is beneficial to switch on cruise control.
If the engine speed rises again with cruise control switched on, the transmission ratio is
changed towards fast again, up to the stored speed at a maximum.
Control by means of the automatic maximum output c cruise control can be damped or
accelerated using the crossgate lever (accelerator ramp switch) on the joystick.
1. Drive for Emergency mode (required in case of failure of the electronic control system)
2. Clutch for the drive
3. Incremental encoder which is a position sensor with digital resolution emitting 8000 pulses per
revolution.
4. Planetary gear i = 192 : 1 (electric motor to actuator shaft)
5. 12 V
DC
electric motor, 0.4 to 7 amps, actuator unit no-load speed of 4500 rpm
6. Slip clutch 2.5 to 3.5 Nm, 4 to 5 Nm at key-operated actuator of emergency control
Example:
Engine speed according to accelerator pedal position
2000 rpm
Setting for automatic maximum output control 10% =
200 rpm
Calculation:
2000 rpm - 180 rpm - 200 rpm =
1620 rpm