Bulletin MSG30-3245-INST/UK
Installation Manual
10
Parker Hannifin
Pump & Motor Division Europe
Chemnitz, Germany
Axial Piston Pump
Series PV, series 44 and higher
Depending on its type, the horse power compensator
consists of a remote pressure com pen sator or a load
sensing compensator in combination with the horse
power pilot cartridge. The opening pressure of this
pilot cartridge depends on the actual displacement
of the pump. At large displacements the opening
pressure is low. As the displacement is reduced
the opening pressure is increased according to the
form of the contour sleeve in the pump. That leads
to the desired control characteristic (constant input
horse power).
That is achieved by having the pilot cartridge seat
being guided by the contour sleeve. This contour
sleeve is firmly connected to the servo piston. The
contour represents the desired input horse power.
The horse power pilot cartridge is internally con-
nected to the compensator valve. Compensator
valves for horse power compensated pumps differ
from standard compensator valves only in the fact,
that a plug in a connecting hole is removed.
For a standard horse power compensator with order-
ing code ...*L* a modified remote pressure compen-
sator is used. For a horse power compensator with
load sensing, code ...*C* a modified load sensing
compensator is used.
Constant horse power curve with adjustment
9. Horse power compensator, codes
...*L*, ...*C*
Adjustment A: tolerance compensation for optimized
performance; done at pilot cartridge.
Adjustment B: maximum pressure setting; done at
integrated pressure pilot valve.
At the adjustment screw of the horse power pilot valve
a basic adjustment of the horse power compensator
can be made. After loosening the lock nut (self sealing
nut) the compensator control curve can be moved
by turning the adjustment screw (adjustment A in
the diagram left). This adjustment, done to meet the
required constant input horse power curve, is already
made during the factory test and should be modified
only in exceptional cases.
To adjust the correct constant horse power curve
a measuring device is required. An output power
measurement requires pressure and flow metering.
An input power measurement requires torque and
speed measurement or a measurement of the electric
motor current.
Note: For horse power control the load sensing dif-
ferential is set to 15 ± 1 bar. Any change will result in
a deviation from the horse power setting.
Note: The setting is very sensitive, 0,1 mm change
of the spindle changes the pressure approximately
20 bar.
Partial section through a horse power controlled
pump
Horse power pilot cartridge
adjustment spindle
lock nut
pilot cartridgecompensator valve
contour sleeve
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