Multiblock; Pressure Compensator Override (Pcor) Function - Danfoss 51 Series Service Manual

Service Manual
Introduction
8
Series 51 Hydraulic Proportional Controls Service Manual
Threshold and Ramp Springs

Multiblock

Some hydraulic proportional controls are used in conjunction with the multiblock. The multiblock is a
manifold with a shuttle-valve that routes high loop (system pressure) from port A or port B to the 4-way
valve to serve as servo supply and to the PCOR function. The shuttle valve also routes the low pressure
side of the loop to the PCOR function.
Multifunction Schematic
BPD Spool
U7
U6
T5
XA
PCOR Valve
Multiblock

Pressure Compensator OverRide (PCOR) Function

The Pressure Compensator OverRide (PCOR) function allows the motor to match its displacement to the
system load. The PCOR overrides the control command allowing the motor to increase displacement
when system pressure reaches a set level due to load. This permits the motor to regulate system pressure
by modulating the displacement of the rotating group. As displacement increases, available torque
increases. Output speed decreases and system pressure remains nearly constant at the PCOR setting.
The PCOR setting is adjustable from 110 to 370 bar [1595 to 5365 psi]. Optional orifices at locations T4, T5,
T6, U6, and U7 regulate the PCOR operation speed.
11009446 • Rev BA • July 2014
Shuttle
L2
A
T4
T6
XB
B
M7
Threshold adjustment screw
P106 438E
Loop Flush
M4 M3
n
max.
disp.
T2 T3
T1
T7 T8
Control
X1
4-Way Valve
locknut
J50
N
M1
L1
M5
M2
P106 417E