58 • vacon description of parameters
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7
t = Par. ID508
t
par. ID515
NX12K23
Motor speed
Output frequency
DC-braking
RUN
STOP
f
out
508 DC-braking time at stop
(2.4.9)
Determines if braking is ON or OFF and the braking time of the DC-brake when the
motor is stopping. The function of the DC-brake depends on the stop function,
parameter ID506.
0 DC-brake is not used
>0 DC-brake is in use and its function depends on the Stop function,
(param. ID506). The DC-braking time is determined with this parameter.
Par. ID506 = 0; Stop function = Coasting:
After the stop command, the motor coasts to a stop without control of 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 ≥ the nominal frequency of the motor, the set value of parameter ID508
determines the braking time. When the frequency is ≤10% of the nominal, the braking
time is 10% of the set value of parameter ID508.
Figure 19. DC-braking time when Stop mode = Coasting.
Par. ID506 = 1; Stop function = Ramp:
After the Stop command, the speed of
the motor is reduced according to the
set deceleration parameters, as fast as
possible, to the speed defined with
parameter ID515, where the DC-
braking starts.
The braking time is defined with para-
meter ID508. If high inertia exists, it is
recommended to use an external brak-
ing resistor for faster deceleration. See
Figure 20.
Figure 20. DC-braking time when Stop mode =
Ramp
f
n
f
n
t
t
t = 1 x Par. ID508
t = 0,1 x Par. ID508
NX12K21
0,1 x f
n
RUN
STOP
RUN
STOP
Output frequency
Motor speed
Output frequency
Motor speed
DC-braking ON
DC-braking ON
f
out
f
out
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