8400 StateLine C | Reference manual
Motor control (MCTRL)
V/f characteristic control (VFCplus)
138 L Firmware ≤ 11.00 - DMS 8.0 EN - 10/2011
5.4.3.5 Torque limitation
The previous chapter, "Optimising the Imax controller
", describes how the drive can be
protected from overload. During commissioning, these settings are carried out once and
remain unchanged afterwards. However, it is often necessary to limit the torque to a lower
value for plant or process reasons.
To avoid overload in the drive train, the torque in motor mode can be limited via the
nTorqueMotLimit_a process input signal, and the torque in generator mode can be
limited via the nTorqueGenLimit_a process input signal:
Identifier
DIS code | data type
Information/possible settings
nTorqueMotLimit_a
C00830/29 | INT
Torque limitation in motor mode
• Scaling: 16384 ≡ 100 % M
max
(C00057)
• Setting range: 0 … +199.99 %
• If keypad control is performed: Parameterisable via C00728/1
.
nTorqueGenLimit_a
C00830/28 | INT
Torque limitation in generator mode
• Scaling: 16384 ≡ 100 % M
max
(C00057)
• Setting range: -199.99 ... 0 %
• If keypad control is performed: Parameterisable via C00728/2
.
Note!
• The actual torque (C00056/2) is directly calculated from the current slip
speed of the machine. This requires correct entry of the motor data. Motor
selection/Motor data ( 107)
• To avoid instabilities during operation with active slip compensation, the
torque limit values are internally processed as absolute values.
• If slip compensation is deactivated (C00021
= 0), indirect torque limitation
(differential signal between the apparent motor current and
nTorqueMotLimit_a or nTorqueGenLimit_a). Above the no-load current of the
motor, the accuracy of the indirect torque limitation is limited.
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