Non Feedback Proportional Electric Control (Nfpe); Control Signal Requirements, Nfpe 115/130 - Danfoss H1 Series Technical Information

Technical Information
H1P 115/130 Axial Piston Single Pumps
Control Options

Non Feedback Proportional Electric Control (NFPE)

© Danfoss | May 2018
The Non Feedback Proportional Electric (NFPE) control is an electrical automotive control in which an
electrical input signal activates one of two proportional solenoids that port charge pressure to either side
of the pump servo cylinder. The NFPE control has no mechanical feedback mechanism.
A serviceable 170 μm screen is located in the supply line immediately before the control porting spool.
Under some circumstances, such as contamination, the control spool could stick and cause the pump to
stay at some displacement.
Non Feedback Proportional Electric Control
P003 192

Control Signal Requirements, NFPE 115/130

The pump displacement is proportional to the solenoid signal current, but it also depends upon pump
input speed and system pressure. This characteristic also provides a power limiting function by reducing
the pump swash-plate angle as system pressure increases.
A typical response characteristic is shown in the accompanying graph below:
Pump displacement vs. input signal
100 %
Signal current (mA)
c b a
"0"
100 %
NFPE schematic
C1
a b c
M14
F00B F00A
BC00000198en-US0901 | 27
C2
T P
P003 188