Charge Pressure
An internal charge relief valve regulates charge pressure. Charge pressure maintains a minimum pressure
in the low side of the transmission loop.
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
/s [150 SUS]. Pumps
configured with no charge pump (external charge supply) are set with a charge flow of 15.0 l/min [4.0 US
gal/min] and a fluid viscosity of 32 mm
2
/s [150 SUS].
The charge pressure setting is referenced to case pressure.
Charge Pump Inlet Pressure
At normal operating temperature charge inlet pressure must not fall below rated charge inlet pressure
(vacuum).
Minimum charge inlet pressure is only allowed at cold start conditions. In some applications it is
recommended to warm up the fluid (e.g. in the tank) before starting the engine and then run the engine
at limited speed until the fluid warms up.
Maximum charge pump inlet pressure may be applied continuously.
Case Pressure
Under normal operating conditions, the rated case pressure must not be exceeded. During cold start case
pressure must be kept 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. Performance may also be affected since charge and system pressure are
additive to case pressure.
Temperature
The high temperature limits apply at the hottest point in the transmission, which is normally the motor
case drain. The system should generally be run at or below the rated temperature.
The maximum intermittent temperature is based on material properties and should never be
exceeded.
Cold oil will not affect the durability of the transmission components, but it may affect the ability of oil to
flow and transmit power; therefore temperatures should remain 16 °C [30 °F] above the pour point of the
hydraulic fluid.
The 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.
Ensure fluid temperature and viscosity limits are concurrently satisfied.
Service Manual
MP1
Operating parameters
36 |
©
Danfoss | April 2019 AX00000244en-000201
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