an error would be triggered one second later and, normally, the drive would
be stopped.
If continuous pressure is permissible even at full stop, the corresponding pressure
can be entered in P 2851[10] - HYD_Pump.
7.11.2.2.2 Pressure-dependent speed regulation characteristic
Image 7.54: Pressure-dependent speed regulation characteristic
For some types of pumps (e.g. internal-gear pumps), negative speeds for very low
pressures (0 bar) are not permitted because in these operating areas, the lubrication
of the pump gear can no longer be ensured. This is why it is possible to configure
the pump characteristic curve in dependence on pressure, which makes it possible
to protect the pump from mechanical destruction (P 2840.14 PumpSpdProt = 1). It is
nonetheless still possible to quickly relieve a high pressure through a negative
pump speed. Using P 2851[14,15]-HYD_Pump, it is possible to configure a
minimum and maximum pressure for negative speeds. The minimum and maximum
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
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7 Control
speed (P 2851.5 nMin and P 2851.6 nMax) from the pump configuration are used
for nMin and nMax. Thus, a negative pump speed is permitted as of the set minimum
pressure for high pressures. The entire speed range can be utilized above the
specified maximum pressure. In the transition range from minimum to maximum
pressure, the speed curve is linear. The speed characteristic of the pump then
behaves a follows:
p
P 2851.15 pMax
P 2851.14 pMin
P 2851.5 nMin
P 2851.6 nMax
n
Image 7.55: Pressure-dependent speed regulation characteristic
