Open Circuit Requirements - Danfoss H1B 060 Service Manual

Service Manual
H1 Bent Axis Motors, Size 060/080/110/160/210/250 cm3
Technical specifications

Open circuit requirements

© Danfoss | August 2018
H1 Bent Axis Motors may be used in Open Circuit (OC) applications.
Since loop flushing is typically not used in OC-applications it is essential to provide sufficient cooling
capacity. This can be done by motor case cross flushing.
The flow rate needs to be adjusted to the cooling demand.
The highest case drain outlet port must always be used for the return flow to the cooler or tank.
The motor case, the control system and the working lines connected to Port A and B must be kept full of
oil at all times, whether in a dynamic or static condition.
The plumbing must not allow the oil to drain down and be replaced with air in the control or rotating
group.
The minimum pressure in the inlet port and the outlet port, measured at gage ports MA and MB, must be
equal or higher as shown in the graphs
16.
Counter balance valves may be used to maintain the minimum pressure requirements. Also the Danfoss
Power Solutions Meter-in / Meter-out PVG technology may be used.
Check valves and sufficient charge pressure supply are also possible.
At no time shall the motor be allowed to operate above the rated speed limits. If flow limiter valves are
used, they must be selected accordingly. Select Motor controls which use the high loop system pressure
to shift the servo piston. This will ensure proper function under all conditions.
Valve blocks, such as counter balance valves attached to the inlet and/or outlet ports, must not interfere
with any part of the motor. A review of the outline drawings or appropriate 3D models must be
completed.
Required inlet pressure diagrams (for cylinder block filling) on page
AX00000025en-US0504 | 17