Sauer Danfoss 51 Series Service Manual page 31

Bent Axis Variable Displacement Motors
Component Adjustment (Continued)
Hydraulic Proportional Control (Types HZ, HS,
H1•H2, and K1•K2)
The control start pressure for these controls may be
adjusted with the adjusting screw on the end cap
(opposite the control block). Control start is that pilot
pressure at which the motor displacement starts to
decrease.
To check the control start setting, install a gauge to
monitor the pilot pressure (connect to port M7 or tee
into the pilot line connected to port X1), and the
minimum angle servo pressure (port M3). If adjusting
an H1 or H2 control, the override solenoid must be
energized. If adjusting a K1 or K2 control, the sole-
noid must not be energized.
NOTE: The pilot signal may be determined by prime
mover speed, other shaft speeds, or other
control pressures, depending upon the de-
sign of the vehicle / machine control circuit.
Increase the pilot signal to the required control start
pressure. An increase in minimum angle servo pres-
sure will be noted as the motor displacement starts to
decrease.
To adjust the control start pressure, loosen the lock
nut using a 10 mm hex wrench and turn the adjusting
screw with a 4 mm internal hex wrench. Turning the
screw clockwise increases the control start pressure.
Torque the lock nut to 9 Nm (6.6 ft•lbsf) after adjust-
ing.
For the H1•H2 controls, the pilot signal pressure
supplied to port X1 should also be present at test port
M7 when the solenoid is energized. When the sole-
noid is not energized, test port M7 should drop to case
pressure.
For the K1•K2 controls, the pilot signal pressure
supplied to port X1 should also be present at test port
M7 when the solenoid is not energized. When the
solenoid is energized, test port M7 should drop to
case pressure.
Shut down the prime mover. Remove the gauges and
install the gauge port plugs. Return the pump and
motor controls to their normal operation.
Servo pressure supply oil is usually provided inter-
nally from the main system ports of the motor. If
external servo pressure supply is utilized, 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 required with the
motor shaft locked.
30 - 9
Fig. 30-15 - Hydraulic Proportional Control,
Type HZ
Fig. 30-16 - Hydraulic Proportional Control,
Type HS
Fig. 30-17 - Hydraulic Proportional Control
with Electric Override, Type H1•H2 (K1•K2
Similar)
Fig. 30-18 - Adjusting Control Threshold,
Types HS, HZ, H1•H2, and K1•K2
Series 51
51000015
51000018
51000020
51000047
31