MDA Technologies 3/2016

02 Engine stop without
additional brake-discharge unit
03 Real-time measurement:
Engine stop without additional
brake-discharge unit
04 Engine stop with additional
brake-discharge unit
02
05 Real-time measurement:
Engine stop with additional
brake-discharge unit
03
04
05
n Green line: under-supply of feeding for
the winch motors
In order to eliminate critical situations
during simulation, an additional brake
discharge valve (3/2 directional valve) has
been added between the integrated brake
discharge valve, the brake-lowering valve
unit, and the multiple disk brake. This integration
can be seen in figure 4.
While disconnecting the engine clutch,
the power declines immediately at the
valve’s solenoid and the additional brake
discharge valve opens the multiple disk
brake directly to the tank. Consequently, the
lifted load stands still immediately. A reaction
time of 50 milliseconds is measured.
The simulation illustrates that in spite of the
feeding pump’s missing fluid volume
(measuring point MI-11) there is no negative
pressure at measuring point MI-9. Therefore,
the load doesn’t slip and is held safely.
The pressure held at measuring point MI-8
between the motor and brake piston resulting
from the ascending lifted load is slowly
reduced via the leakages before taking effect
on the multiple disk brake.
Figure 5 shows again a realistic comparison
with the real-time measurement. In
the operational case “stop by outage of
diesel engine”, the multiple disk brakes
(black line) are immediately engaged while
the load is safely held mechanically and no
longer hydraulically held by the piston of
the brake-lowering valve. The load and
brake pressure is slowly reduced via the
leakage. Hence, a safe operation of the
winch can be ensured.
With Automation Studio, the operational
capability of the original design was verified
through simulation. Thus, designing a
defective set-off without an additional
braking valve could be anticipated. Possible
injuries to people and property damage
could also be prevented.
www.famictech.com
MDA Technologies 3/2016