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KFU 2-/4-
120
11.5 Search
Run
The synchronization to a rotating drive is necessary in applications which drive the
motor by their behavior or in which the drive is still rotating after a fault switch-off. Via
Operation mode search run
645
, the motor speed is synchronized to the current mo-
tor speed without an "Overcurrent" fault message. After this, the motor is accelerated
to the reference speed at the set acceleration. This synchronization function deter-
mines the current rotary frequency of the drive via a search run in operation modes 1
to 5.
The synchronization in operation modes 10 to 15 is accelerated by short test im-
pulses. Rotary frequencies of up to 250 Hz are determined within 100 ms to 300 ms.
For higher frequencies, a wrong frequency is determined and the synchronization
fails. In the "Quick synchronization" operation modes, the search run cannot deter-
mine whether a synchronization attempt has failed.
Operation mode 645
Function
0 -
Off
The synchronization to a rotating drive is deactivated.
1 -
Search Dir. acc. to
Preset Val.
The search direction is defined by the sign in front of the
reference value. If a positive reference value (clockwise
field of rotation) is entered, the search is in a positive di-
rection (clockwise field of rotation), with a negative refer-
ence value, the search is in a negative direction (anti-
clockwise field of rotation).
2 -
First clockw.
then anticlockw.,
DCB
The first attempt is to synchronize to the drive in positive
direction (clockwise field of rotation). If this attempt fails,
it is tried to synchronize to the drive in negative direction
(anticlockwise field of rotation).
3 -
First anticlockw.
then clockw.,
DCB
The first attempt is to synchronize to the drive in nega-
tive direction (anticlockwise field of rotation). If this at-
tempt fails, it is tried to synchronize to the drive in posi-
tive direction (clockwise field of rotation).
4 -
Clockw. only,
DCB
Synchronization to the drive is only done in positive di-
rection (clockwise field of rotation).
5 -
Anticlockw. only,
DCB
Synchronization to the drive is only done in negative
direction (anticlockwise field of rotation).
10 -
Quick Synchroniza-
tion
An attempt is made to synchronize to the drive in positive
direction (clockwise field of rotation) and in negative
direction (anticlockwise field of rotation).
11 -
Quick Synch. acc. to
Preset Value
The search direction is defined by the sign in front of the
reference value. If a positive reference value (clockwise
field of rotation) is entered, the search is in a positive di-
rection (clockwise field of rotation), with a negative refer-
ence value, the search is in a negative direction (anti-
clockwise field of rotation).
14 -
Quick synch.,
clockw. only
Synchronization to the drive is only done in positive di-
rection (clockwise field of rotation).
15 -
Quick synch.,
anticlockw. only
Synchronization to the drive is only done in negative
direction (anticlockwise field of rotation).
Operation modes 1, 4 and 5 define a direction of rotation for the search run and avoid
a deviating direction. The search run can accelerate drives by checking the rotary
frequency if the drives have a low moment of inertia and/or a small load moment.
In operation modes 10 to 15, it cannot be ruled out that a wrong direction of rotation is
determined in quick synchronization. For example, a frequency not equal to zero may
be determined although the drive is at a standstill. If there is no overcurrent, the drive
is accelerated accordingly. The direction of rotation is defined in operation modes 11,
14 and 15.