Current - regulated ( speed variation possible)
The stirrer can deliver doubled output for a short time to even
out load peaks which could, for instance, occur if solid or semi-
pourable agents are added. If operations continue in the over-
load range for a long time (eg process-related increase in vis-
cosity), the speed is reduced until the stirrer torque corre-
sponds to the nominal torque of the machine. The possible
speed is continually adapted to operating conditions, guarante-
eing that speed is as close as possible to the NOMINAL speed
set.
Version
EUROSTAR power basic
To protect the machine from overloading, the speed is reduced
if the machine has been operating for some time in overload
mode. The NOMINAL speed (scale value) set then does not
correspond to the ACTUAL speed of the output shaft. This
condition is indicated by flashing of the yellow control light (C)
(overload opera tion)
Versions
EUROSTAR power control - visc,
EUROSTAR power control - visc P1,
EUROSTAR power control - visc P4,
EUROSTAR power control - visc P7,
und
EUROSTAR power control - visc 6000
A distinction is made here between two different conditions:
-
S
et
V
alue =
P
rocess
V
alue (flashing)
: (Fig. 4)
The machine is already running in the overload range, but the
NOMINAL speed (SV) does not yet correspond to the ACTUAL
speed (PV). This condition is maintained so long as neither the
motor current nor the temperature exceed the permitted limit
values.
-
S
et
V
alue >
P
rocess
V
alue (flashing)
: (Fig. 5)
#
The machine is running in the overload range, speed is redu-
ced. The ACTUAL speed of the stirrer shaft (PV) is smaller
than the NOMINAL speed set (SV). The ACTUAL speed is
regulated by output. The machine can be operated perma-
nently in this condition provided the output shaft is not stalled.
The indicator is extinguished when the load is reduced accor-
dingly or the NOMINAL speed is adapted to the possible
ACTUAL speed.
If there is a fluctuating load which is over double the nominal
torque, the speed is reduced immediately.
The status indicator then shows the second condition (SV>PV
flashing).
With the stirrer appliances EUROSTAR power control-visc,
EUROSTAR power control-visc P1, P4, P7 and EUROSTAR
power control-visc 6000 it is possible on the basis of the inte-
grated torque trend measurement to indicate the torque acting
on the stirrer shaft on the LCD display. In addition the torque
value on the EUROSTAR power control-visc is displayed via
the serial interface and on the EUROSTAR digi-visc and
EUROSTAR power digi-visc via the analogue output.
Absolute torque measurement is not possible with these
machines.
By touching the illuminated key (F) ”Mode” (for approx. 1 sec.)
the LCD display can be changed over to show the torque value
in Newton centimetres (Ncm). (Fig. 6).
Only the relative change in torque in relation to a starting point
determined by the user is measured, indicated and output.
To obtain the most precise values possible in torque trend
measurement it is necessary for the machine to have achieved
its operating temperature (pre-running time 10-15 min.).
Speed - overload operation
Torque indicator
EUSTAR0707
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