Series 51 Hydraulic Proportional Controls HZ, HA ... - Sauer-Danfoss

Series 51 Hydraulic Proportional Controls
Service Manual
Adjustments
Threshold Setting Checking Threshold Setting
1. Install a 50 bar [600 psi] gauge at port M3 to read minimum servo pressure.
12 11009446 • Rev AC • November 2010
2. Install a 50 bar [600 psi] gauge at port M4 to read maximum servo pressure.
3. Install meter to read signal current.
4. Increase the signal current to the proper setting.
The pressure at port M3 should rise to about 100 psi [6.89 bar] higher than the pressure
at port M4. This causes the servo piston to move toward minimum position. Signal
current at this point is the threshold setting.
On a test stand, increase signal current until the flow from the motor begins to decrease.
The signal current at this point is the threshold setting.
Adjusting Threshold Setting
1. Using a 10 mm wrench, loosen the
locknut on the adjustment screw.
2. Using a 3 mm internal hex wrench
turn the adjusting screw:
• Clockwise (cw) to increase the
setting
• Counterclockwise (ccw) to
decrease the setting.
3. While holding the position of the
adjustment screw:
• tighten the locknut
• using a 10 mm wrench torque
the locknut to 9 N•m [6.6 lbf•ft].
Locknut and Threshold
Locknut
10 mm
9 Nm [6.6 lbf•ft]
Adjusting screw
Spring seat
P101 911