User guide

Lenze · 8400 BaseLine C · Reference manual · DMS 1.6 EN · 01/2014 · TD05 77
5 Motor control (MCTRL)
5.3 Defining current and speed limits
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 How to adapt the peak current limitation:
V/f characteristic control (VFCplus):
• Reduce the slip compensation with C021
.
V/f control (VFCplus + encoder):
•Reduce V
min
boost inC016.
Sensorless vector control (SLVC):
• Reduce the slip compensation with C021
.
• Reduce the limitation of the torque in motor mode via nTorqueMotLimit_a (C728/1
) and
the limitation of the torque in generator mode via nTorqueGenLimit_a (C728/2
).
 Note!
Highly dynamic applications
(that have e.g. too short acceleration/deceleration times or excessively changing loads)
The overcurrent disconnection may respond (fault message OC1), if the setting of the
maximum current in motor mode in C022
approximately corresponds to the maximum
permissible value of the respective inverter.
Remedies:
• Increase of the acceleration and deceleration ramp times
• Reduction of the maximum current in motor mode (C022
)
• Reduction of the maximum current in generator mode (C023
)
• Adaptation of the indirect peak current limitation (procedure depends on the selected
motor control mode, see below)
• Reduction of the reset time of the current limiting controller (C074/1
)
Influencing the torque in motor/generator mode
The torque in motor and generator mode can be limited via the nTorqueMotLim and
nTorqueGenLim process signal inputs.
• If V/f characteristic control (VFCplus) is selected, limitation is indirectly
performed via
a so-called I
max
controller.
• If sensorless vector control (SLVC) is selected, the limitation has a direct
effect on the
torque-producing current component.
If keypad control is selected, the nTorqueMotLim and nTorqueGenLim process signals can
be parameterised via C728/1...2
.