Table 154: Selections for parameter ID508
Selection
number
Selection name
Description
0
DC-brake is not used
>0
DC-brake is in use and its func-
tion depends on the Stop func-
tion, (parameter ID506). The
DC-braking time is determined
with this parameter.
PARAMETER ID506 = 0; STOP FUNCTION = COASTING:
After the stop command, the motor coasts to a stop without control of the AC drive.
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.
A
A
B
C
B
C
t
f
out
f
n
f
n
Output
frequency
t=1 x Par. ID508
RUN
STOP
t
f
out
0.1 x f
n
t=1 x Par. ID508
RUN
STOP
Fig. 68: DC-braking time when Stop mode = Coasting
A. Output frequency
B. Motor speed
C. DC-braking ON
PARAMETER 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 parameter ID508. If high inertia exists, it is recommended to
use an external braking resistor for faster deceleration.
PARAMETER DESCRIPTIONS
VACON · 305
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