The charge pressure setting listed in the order code is the set pressure of the charge relief valve with the
pump in neutral, operating at 1800 min
-1
(rpm), and with a fluid viscosity of 32 mm
2
/sec [150 SUS]. The
charge pressure setting is referenced to case pressure (the differential pressure above case pressure).
Charge flow to pump must be sufficient to provide adequate charge pressure.
Charge inlet pressure
At normal operating temperature charge inlet pressure must not fall below rated charge inlet pressure.
Minimum charge inlet pressure is only allowed at cold start conditions. In some applications you may
need to warm up the fluid (start the prime mover without using the vehicle/machine functions) before
moving the vehicle or operating the machine.
Case pressure
Do not exceed rated case pressure under normal operating conditions. During cold start, keep case
pressure below maximum intermittent case pressure. Size drain plumbing accordingly.
Caution
Possible component damage or leakage
Operation with case pressure in excess of stated limits may damage seals, gaskets, and/or housings,
causing external leakage. This condition may also affect performance since charge and system pressure
are referenced to case pressure.
Temperature and viscosity
Temperature
High temperature limits apply at the hottest point in the transmission loop, which is normally the motor
case drain. Ensure the system generally runs at or below the rated temperature. The maximum
intermittent temperature is based on material properties: Never exceed it.
Cold oil will generally not affect the durability of the transmission components, but it may affect the
ability of oil to flow and transmit power: therefore ensure temperatures remain 16 °C [30 °F] above the
pour point of the hydraulic fluid. Minimum temperature relates to the physical properties of component
materials.
Size heat exchangers to keep the fluid within these limits. Danfoss recommends testing to verify that
these temperature limits are not exceeded.
Viscosity
For maximum efficiency and bearing life, ensure the fluid viscosity remains in the recommended range.
Minimum viscosity should be encountered only during brief occasions of maximum ambient
temperature and severe duty cycle operation. Maximum viscosity should be encountered only at cold
start.
Service Manual
H1 45/53/60/68 Tandem Closed Circuit Axial Piston Pumps
Operating parameters
©
Danfoss | June 2018 520L0928 | AX00000103en-US0303 | 21
To Next Page
Loading...
Need help?
General
