VersiStart i III
34
8.6
Stop Methods
Soft starters offer a variety of methods for the control of motor stopping.
Stop Method
Performance Result
Coast To Stop
Natural load run down
TVR Soft Stop
Extended run down time
Adaptive Control
Extended run down time according to selected deceleration profile
Brake
Reduced run down time
Soft starters are often used in pumping applications to eliminate the damaging effects of fluid hammer. Adaptive Control should be the
preferred stop method for these applications.
8.6.1
Coast to Stop
Coast to stop lets the motor slow at its natural rate, with no control from the soft starter. The time required to stop will depend on the
type of load.
8.6.2
TVR Soft Stop
Timed voltage ramp reduces the voltage to the motor gradually over a defined time. The load may continue to run after the stop ramp is
complete.
Timed voltage ramp stopping can be useful for applications where the stop time needs to be extended, or to avoid transients on
generator set supplies.
Vol
tage (
%
ful
l v
ol
tage)
1
1: Stop Time (parameter 2I)
Time
8.6.3
Adaptive Control for Stopping
In an adaptive control soft stop, the VersiStart i III controls the current in order to stop the motor within a specified time and using a
selected deceleration profile. Adaptive Control can be useful in extending the stopping time of low inertia loads.
NOTE
Adaptive control does not actively slow the motor down and will not stop the motor faster than a coast to stop. To
shorten the stopping time of high inertia loads, use brake.
CAUTION
Adaptive Control controls the motor's speed profile, within the programmed time limit. This may result in a higher level
of current than traditional control methods.
Every application has a particular stopping profile, based on characteristics of the load and the motor. Adaptive Control offers three
different stopping profiles. Choose the adaptive control profile that best matches your application requirements.
Adaptive Control
To use Adaptive Control to control stopping performance:
1.
Select Adaptive Control from the Stop Mode menu (parameter 2H)
2.
Set the desired Stop Time (parameter 2I)
3.
Select the required Adaptive Stop Profile (parameter 2K)
