Lenze 8400 - Page 155

Lenze · 8400 HighLine · Reference manual · DMS 12.0 EN · 06/2017 · TD23 155
5 Motor control (MCTRL)
5.3 Defining current and speed limits
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Current limitation in motor and generator mode
In the various motor control modes, the inverter is provided with functions which determine the
dynamic behaviour under load and counteract exceedance of the maximum current in motor or
generator mode.
The current limits must be selected depending on
• the permissible maximum current of the motor  recommendation: I(Mot)
N
< 1.5 ... 2.0
• the permissible maximum current of the inverter
• the torque in motor/generator mode required for the application
Parameters Info Lenze setting
Value Unit
C00022 Imax in motor mode 47.00 A
C00023
Imax in generator mode
• 100 % ≡ Imax in motor mode (C00022
)
100 %
 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 or oC11) if the setting of
the maximum current in motor mode in C00022
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 (C00022
)
• Reduction of the maximum current in generator mode (C00023
)
• 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 (C00074/1
)
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), sensorless control for synchronous motors (SLPSM)
or servo control (SC) is selected, 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 C00728/1...2
.