Overview
This section defines the operating parameters and limitations for LPV pumps with regard to input speeds
and pressures. For actual parameters, refer to
on page 20.
Input speed
on page 20, gives rated and maximum speeds for each
displacement. Not all displacements operate under the same speed limits. Definitions of these speed
limits appear below.
Continuous speed is the maximum recommended operating speed at full power condition. Operating at
or below this speed should yield satisfactory product life. Do not exceed maximum pump speed during
unloaded, on-road travel over level ground.
Maximum speed is the highest operating speed permitted. Exceeding maximum speed reduces pump
life and can cause loss of hydrostatic power and braking capacity. Never exceed the maximum speed
limit under any operating conditions.
W
Warning
Unintended vehicle or machine movement hazard.
The loss of hydrostatic drive line power, in any mode of operation (forward, neutral, or reverse) may cause
the system to lose hydrostatic braking capacity. You must provide a braking system, redundant to the
hydrostatic transmission, sufficient to stop and hold the vehicle or machine in the event of hydrostatic
drive power loss.
System pressure
on page 20, gives maximum and maximum working pressure
ratings for each displacement. Not all displacements operate under the same pressure limits. Definitions
of the operating pressure limits appear below.
Pressure Ratings
System pressure is the differential pressure between high pressure system ports. It is the dominant
operating variable affecting hydraulic unit life. High system pressure, which results from high load,
reduces expected life. Hydraulic unit life depends on the speed and normal operating, or weighted
average, pressure that can only be determined from a duty cycle analysis.
Application pressure is the high pressure relief or pressure limiter setting normally defined within the
order code of the pump. This is the applied system pressure at which the driveline generates the
maximum calculated pull or torque in the application.
Maximum Working pressure is the highest recommended application pressure. Maximum working
pressure is not intended to be a continuous pressure. Propel systems with application pressures at, or
below, this pressure should yield satisfactory unit life given proper component sizing.
Maximum pressure is the highest allowable application pressure under any circumstance. Application
pressures above maximum working pressure will only be considered with duty cycle analysis and factory
approval.
Minimum low loop pressure must be maintained under all operating conditions to avoid cavitation.
All pressure limits are differential pressures referenced to low loop (charge) pressure. Subtract low loop
pressure from gauge readings to compute the differential.
Viscosity
Maintain fluid viscosity within the recommended range for maximum efficiency and bearing life.
Minimum viscosity should only occur during brief occasions of maximum ambient temperature and
Technical Information
LPV Axial Piston Pumps
Operating parameters
8 |
©
Danfoss | September 2017
520L0954 | BC00000044en-US0102