KFU 2-/4-
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11.2.1 Switch-Off
Threshold
The
Switch-off threshold stop function
637
defines the frequency as from which a
standstill of the drive is recognized. This percentage parameter value is relative to the
set
Maximum frequency
419
.
The switch-off threshold is to be adjusted according to the load behavior of the drive
and the device output, as the drive must be controlled to a speed below the switch-off
threshold.
Parameter
Settings
No.
Description
Min.
Max.
Fact. sett.
637 Switch-off threshold
0.0 %
100.0 %
1.0 %
Attention!
If the motor builds up a stopping torque, it may be possible that the
switch-off threshold stop function is not reached due to the slip fre-
quency and the standstill of the drive is not recognized. In this case,
increase the value of the
Switch-off threshold stop function
637
.
11.2.2 Holding
Time
The
Holding time stop function
638
is considered in stopping behavior 1, 3, 4 and
stopping behavior 6. Controlling to speed zero leads to a heating of the motor and
should only be done for a short period in internally ventilated motors.
Parameter
Settings
No.
Description
Min.
Max.
Fact. sett.
638 Holding time stop function
0.0 s
200.0 s
1.0 s
11.3
Direct current brake
Stopping behaviors 3, 6, 7 and the search run function include the direct current
brake. Depending on the setting of the stop function, a direct current is impressed into
the motor either directly or, when it is at a standstill, after the demagnetization time.
The impression of the
Braking current
631
results in the motor heating up and should
only be done for a short period in the case of internally ventilated motors.
Parameter
Settings
No.
Description
Min.
Max.
Fact. sett.
631 Braking current
0.00 A
2
I
FUN
2
I
FUN
The setting of the parameter
Braking time
632
defines the time-controlled stopping
behavior. Contact-controlled operation of the direct current brake is activated by en-
tering the value zero for the
Braking time
632
.
Time controlled:
The direct current is controlled by the status of the signals Start clockwise and Start
anticlockwise. The current set by the parameter
Braking current
631
flows until the
time set by the parameter
Braking time
632
has expired.
For the duration of the braking time, the control signals Start clockwise and Start anti-
clockwise are logical 0 (Low) or 1 (High).