Vacon CX - Page 34

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Page 34 Vacon
Pump and fan control with autochange
4. 9 DC braking time at stop
Defines if braking is ON or OFF and braking time of the DC-brake when the motor is
stopping. The function of the DC-brake depends on the stop function, parameter 4.
7. See figure 6-14.
0 DC-brake is not used
>0 DC-brake is in use and its function depends on the Stop function,
(param. 4. 7), and the time depends on the value of parameter 4. 9:
Stop-function = 0 (coasting):
After the stop command, the motor coasts to a stop without any control from
the frequency converter.
With DC-injection, the motor can be electrically stopped in the shortest possible
time, without using an optional external braking resistor.
The braking time is scaled according to the frequency when the DC-
braking starts. If the frequency is >nominal frequency of the motor (par. 1.11),
the setting value of parameter 4.9 determines the braking time. When the
frequency is <10% of the nominal, the braking time is 10% of the set
value of parameter 4.9.
Stop-function = 1 (ramp):
After the Stop command,
the speed of the motor is
reduced according to the
set deceleration para-
meters, as fast as
possible, to a speed
defined with the parameter
4. 10, where the DC-
braking starts. The braking
time is defined with para-
meter 4. 9. If high inertia
exists, it is recommended
to use an external braking
resistor for faster
deceleration. See figure
6-15.
t = param. 4. 9
t
Param. 4. 10
f
out
UD009K23
Motor speed
Output frequency
DC-braking
RUN
STOP
0,1x f
n
Figure 6-14 DC-braking time when par. 4. 7 = 0.
f
out
f
out
f
n
f
n
t
t
t = 1 x par. 4. 9
t = 0.1 x par. 4. 9
UD009K21RUN
STOP
RUN
STOP
Output frequency
Motor speed
Output frequency
Motor speed
DC-braking ON
DC-braking ON
Figure 6-15 DC-braking time when par. 4. 7 = 1.