Drive Balance Control (Dbc); Verifying The Function Of The Dbc; Acd: Transmission Speed Sensor - Valtra 6000 Workshop Manual

32. ACB / ACD electro---hydraulic power lift
D. Drive Balance Control (DBC)
When a tractor is driven in transport drive and a heavy
implement is attached to the power lift linkage, this causes
oscillation of the tractor (front wheels tend to jump up from
the ground) . ACB/ACD power lift has the Drive Balance
Control (oscillation damping), which functions when the
power lift is in the transport position. Shocks from an imple-
ment cause tensions in the draft sensors, and these ten-
sions alter to electric signals, which in turn cause that the
linkage makes small lift and lowering movements.
Drive Balance Control is activated, when the fol-
lowing four terms are valid:
a) Power lift is activated
b) Power lift is in transport position
c) Drive Balance Control is switched on (ind. light lights).
d) ACD: Transmission frequency signal (driving speed) is
greater than the value, which has been saved in the memory
of the control unit.
When these four terms are valid, the lower links lower about
4 % from the upper limit position to the intermediate limit posi-
tion.
The lower links can lower 4 % from the intermediate limit posi-
tion to the lower limit position. Thus the max. distance
between the upper limit position to the lower limit position is
8 %. All percentages are counted from the total movement
range of the lower links (100 %).
Note! Position of the lowering speed selector does not affect
the Drive Balance Control speed.
Note! ACD: The Drive Balance Control is switched off auto-
matically, if the driving speed drops 25 % below the speed
which is saved in the memory of the ACD.
ACD: Adjusting the switch-- on driving speed
The DBC is switched on automatically in the transport mode,
when the driving speed is about 8 km/h (when the above gfour
terms are in operation).
The switch ---on driving speed can be changed as follows:
a) Adjust with the lowering speed selector to the minimum
Not slip contr.
lowering speed.
on ACB
b) Adjust the position control potentiometer to the max
upper position
c) Drive with the tractor at the required switch ---on speed.
The tractor must be in motion i.e. the transmission fre-
quency signal should be greater than 25 Hz.
d) Turn the lift/lower switch at least four times to the trans-
port position during three seconds (CONTROL ---TRANS-
PORT).
e) The frequency signal from the sensor remains in the
memory of the ACD. After this the diagnostic lights flash for
three seconds with frequency of ca. 8 Hz, which confirms
that a new switch ---on speed for the DBC is valid.
The DBC is activated automatically, when the signal from
the transmission speed sensor (driving speed) exceeds the
value in the memory.
The DBC can be switched off with the selector on ACB and
ACD.

Verifying the function of the DBC

When the tractor is driven in transport driving on an uneven
road or field with an heavy implement attached to the
power lift linkage, the shocks caused by the implement
must light the indicator lights for lifting and lowering. This
indicates that the DBC is functioning (the draft sensors
react to shocks from the implement).
When the DBC is activated, and tractor driving speed
exceeds the switch ---on speed, the indicator light for the
lowering must light for a while, since the lower links lower 4
% to the intermediate limit position.

ACD: Transmission speed sensor

The sensor is placed on the RH side of the reverse shuttle
housing. The sensor is the same and in the same place as
on AC IV unit, see page 351/3 sensor B2C, or on Agro-
data ---instrument, see page 331/4 sensor B6.
Removing, fitting and adjustment of the sensor is done in
the same way as on AC IV ---unit or on Agrodata ---instru-
ment.
Note! The fault code no 42 indicates that there are mal-
functions in sensor wires or in the sensor. Checking the
DBC selector, see instr. F.
309
Model
15. 5. 1996
8450-- 8750
1. 11. 1998
Code Page
321 5