Firmware
≤
11.00 - DMS 8.0 EN - 10/2011
L
159
8400 StateLine C | Reference manual
Motor control (MCTRL)
V/f control (V encoder)
Controller limitation
Max. intervention of the controller is limited by the controller limitation (
C00971/1
).
The controller can be limited depending on the application.
We recommend to limit the max. intervention to twice the rated slip of the motor.
The rated slip is calculated as follows:
[5-9]
Calculation of the rated slip
Slip limitation
In addition to limiting the slip regulator, the field frequency to be injected can also be
limited by another limiting element, the slip limitation (
C00971/2
).
A slip limitation to, for instance, double the rated slip of the motor prevents the motor
from stalling in very dynamic processes.
Motor stalling is caused by:
– High overcurrent at very steep speed ramps
– very fast speed changes due to load, e.g. abrupt stopping of the drive due to an
encounter with a stop or a load that is not moving.
f
Slip
Rated
Hz
[
]
f
Rated
Hz
[
]
n
Motor
Rated
rpm
[
]
60
------------------------------------------
p
Number of pole pairs
⋅
⎝
⎠
⎛
⎞
–
=
Note!
The setting
C00971/1
= 0 Hz deactivates the slip regulator. In this case, the
structure of the V/f control corresponds to the structure of the V/f characteristic
control without feedback.
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