Neutral adjustment (EDC) (bottom view)
Solenoid shaft
Feedback pin
Adjusting
screw
(cam)
P106 046E
Maximum
adjustment
less than 120°
Control spool
Illustration shows how eccentric cam on adjusting screw rotates to adjust neutral.
Mechanical neutral adjustment
W
Warning
Unintended movement of the machine or mechanism may cause injury to the technician or bystanders.
To protect against unintended movement, secure the machine or disable/disconnect the mechanism
while servicing.
Mechanical neutral is set with the pump running at 1800 min¯¹(rpm). To set neutral, you must stroke the
pump in each direction. 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. The procedure is the same
for each side of each pump so you will need to repeat it four times to set mechanical neutral for both the
front and rear sections. 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 or MC and MD
•
Pressure differential between M4 and M5 (optional)
•
Pressure differential between A and B or C and D (optional)
Refer to
Pressure measurements
on page 26 and the illustration on the next page for gauge port locations
and information.
Service Manual
H1 45/53/60/68 Tandem Closed Circuit Axial Piston Pumps
Adjustments
42 |
©
Danfoss | June 2018
520L0928 | AX00000103en-US0303
