Displacement Control Adjustments - Sauer Danfoss 51 Series Manual

HYDRAULIC PUMP
6.4

Displacement Control Adjustments:

Electro -- hydraulic Proportional Control Type EQ
NOTE
A change in motor displacement
can be detected by providing a
constant flow of fluid to the motor
and monitoring the motor output
shaft speed while adjusting the con-
trol. An increase in displacement
will result in a decrease in shaft
speed, while a decrease in displace-
ment will result in an increase in
shaft speed.
The control start current for the EQ controls is adjusted
with the adjusting screw on the end cap (opposite the
control block). Refer to Figure 9. Control start is the
current supplied to the PCP (Pressure Control Pilot)
valve at the point which the motor displacement starts to
decrease.
Figure 9. EQ Type Control
To check the threshold setting:
(1) Install a test meter to monitor the PCP cur-
rent, and a pressure gauge to monitor the
minimum angle servo pressure (port M3).
(2) Increase the control start current. An in-
crease in minimum angle servo pressure will
be noted as the motor displacement starts
to decrease.
(3) Adjust the control start current by loosening
the lock nut using a 10 mm hex wrench and
turning the adjusting screw with a 4 mm in-
ternal hex wrench (Fig. 10). Turning the
screw clockwise increases the control start
current. Torque the locknut to 6.6 ft. lbs (9
Nm) after completing the adjustment.
Figure 10. Adjusting Control Threshold
NOTE
PCP supply pressure oil is provided
externally. PCP supply pressure
must be a minimum of 20 bar (290
psi) and no more than 70 bar (1015
psi). If servo pressure supply oil is
provided externally, a minimum of
25 bar (360 psi) is required to
change the motor displacement
with the motor shaft turning, and a
minimum of 70 bar (1015 psi) is re-
quired with the motor shaft locked.
GROUP 3025
3025- - 9A, Page 11