Danfoss 51 Series Service Manual

Overview
W
Warning
This service procedure may require disabling the vehicle / machine (raising the wheels off the ground,
disconnecting the work function, and so forth) while performing, in order to prevent injury to the
technician and bystanders. Take the necessary safety precautions
Adjust components of the Series 51 and Series 51-1 motors per following procedures (where necessary,
refer to Pressure measurements on page 23, for gauge port locations and sizes):
Charge pressure relief valve
Set the charge pressure relief valve to the model order code specifications. In most applications, the
motor charge relief valve is set 2 to 4 bar [29 to 58 psi] below the setting of the pump charge relief valve
(measured with the pump in its neutral or zero-angle position). This setting assumes a reservoir
temperature of 50° C [122° F]. Charge pressure is referenced (additive) to case pressure.
Measuring charge pressure
1. Install a 0 to 60 bar [0 to 1000 psi] pressure gauge in port M1 or M2 (use which ever is at low loop
pressure).
2. Install a 0 to 60 bar [0 to 1000 psi] gauge in port L1 or L2 to measure case pressure.
3. Operate the system with the prime mover at normal operating speed and the pump at half stroke
(forward or reverse).
Series 51 charge pressure relief valve
Adjustment
plug
1
1
/
16
lock nut
P101 208E
Older Series 51 and Series 51-1 motors may be equipped with an external screw adjustable charge
pressure relief valve (not shown).
Adjusting charge pressure
W
Warning
Incorrect charge pressure settings may result in the inability to build required system pressure and / or
inadequate loop flushing flows. You must maintain the correct charge pressure under all operation
conditions to maintain pump performance
1. Loosen the lock nut using a 11/16 hex wrench.
2. Turn the adjustment plug with a large screwdriver or 13mm hex wrench.
Clockwise rotation of the plug increases the setting, and counterclockwise rotation decreases the
setting. The charge pressure setting will be reduced or increased at a rate of approximately 3.4 bar [50
psi] per turn.
Service Manual
Series 51 and 51-1 Motors
Adjustments
32 |
©
Danfoss | March 2016 11008567 | AX00000013en-US0202

Danfoss 51 Series Specifications

General

Power Output	Unknown
Cylinders	Unknown
Fuel Type	Unknown
Cooling System	Unknown
Aspiration	Unknown