7. Rotate the neutral adjusting screw counterclockwise until the pressure increases by an equal amount
on the other gauge.
Note the angular position of the wrench.
8. Rotate the neutral adjusting screw clockwise half the distance between the wrench positions noted
above.
The gauges should read the same pressure, indicating that the control is in its neutral position.
9. Hold the neutral adjusting screw stationary and tighten the locknut (D060). Torque to 12 N•m [9
lbf•ft].
C
Caution
Do not over torque.
10. When the neutral position is set, stop the prime mover and remove the gauges.
11. Install the gauge port plugs.
12. Reconnect the external control input.
A small pressure differential of 1.5 bar [22 psi] or less is acceptable. Zero differential is usually not
possible.
Mechanical Neutral Adjustment
Mechanical neutral is set with the pump running at 1800 min
-1
(rpm). To set neutral, you must stroke the
pump in each direction. The procedure is the same for each side of each pump for both the front and rear
sections.
You can do this with a small movement of the eccentric screw on EDC controls, however non-feedback
controls (NFPE/FNR) lack this mechanism. To stroke a pump with non-feedback control, you must provide
a 100 Hz PWM signal to the control solenoids. If you perform this adjustment with the pump installed in a
vehicle or machine, safely elevate the wheels or disconnect the mechanism to allow safe operation
during adjustment.
This procedure details setting neutral for the entire pump, one side at a time. Alternate M4/M5 and
MA/MB to zero out forward and reverse directions of the front unit, then move the gauges to M4/M5 of
the rear unit and MC/MD (system gauge ports for the rear unit). Refer to the drawing on the next page to
identify all ports. The front and rear sections are basically mirror images of each other. The control
solenoids C1 and C2 are marked on each control.
While performing this adjustment, you monitor the following pressures:
•
Servo pressure at M4 and M5
•
System pressure at MA and MB
•
Pressure differential between M4 and M5 (optional)
•
Pressure differential between A and B (optional)
Unintended Machine Movement
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
Secure the machine or disable/disconnect the mechanism while servicing to protect against unintended
movement.
Pump Setup
The figure below shows the locations of system and gauge ports you use when adjusting the servo
neutral postion.
Service Manual
H1P 069—H1P 250 Axial Piston Single Pumps
Adjustments
40 |
©
Danfoss | September 2020
AX152886482551en-000504
