Counter pressure operation
Counter pressure operation is needed mainly in series connection (see
Motors in
parallel or series circuit
on page 26). Counter pressure operation means using the
motor with high back pressure in the return line.
The counter pressure operation affects the torque output of the motor due to
decreased pressure difference over the working lines.
Attention:
Make sure the combined pressure in the working lines does not exceed the
permissible values of the working pressure during counter pressure
operation.
Counter pressure operation is not recommended, because high back
pressure stresses the motor more than usual operation.
Hydrostatic braking
Hydrostatic braking means using the output torque of the motor to decelerate the
speed. The output torque is generated by closing the return line of the motor, in
which case a working pressure will form in the return line. The minimum pressure and
feed flow must be maintained in the feed line of the motor during hydrostatic braking.
Note:
The hydrostatic braking requires an active hydraulic fluid supply.
Danger:
Do not use the hydrostatic braking without relief valves in the working
lines. When an external load is rotating the motor, the hydraulic pressure
may increase indefinitely. This leads to danger if a hydraulic hose or
component brakes under high pressure.
Short circuit operation
Short circuit operation means connecting the return flow of the motor directly to the
feed line of the motor.
Short circuit operation is needed, if the motor must be rotated faster than the
hydraulic system can supply and freewheeling the motor is not possible (see
Mechanical freewheeling
on page 19).
Make sure the minimum pressure is maintained in both working lines of the motor
during short circuit operation.
Note:
The short circuit operation requires an active hydraulic fluid supply.
Attention:
Make sure the motor does not overheat during short circuit operation.
4.1.3
4.1.4
4.1.5
System Design
28
Product Manual
