Lenze 8400 StateLine - Manual (Page 136)

5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
136
Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
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Motor in continuous operation up to 0.5 n
rated
• for self-ventilated motors: I
motor
≈ 0.8 I
rated motor
• for forced ventilated motors: I
motor
≈ I
rated motor
5.4.3.3 Optimising the Imax controller
Using the Lenze setting of the current limitation controller, the drive is stable:
Most applications do not require optimisation.
The setting of the current limitation controller must be adapted if
• power control including great moments of inertia is performed.
• Recommendation: Increase of the reset time Ti ( C00074/1 ) of the I
max
controller.
• vibrations occur in the V/f control (VFCplus + encoder) mode during the intervention of the
current limitation controller.
• Recommendation: Increase of the reset time Ti ( C00074/1 ) of the I
max
controller.
• overcurrent errors (e.g. OC3) occur due to load impulses or too high acceleration ramps.
• Recommendation: Reduction of the gain Vp ( C00073/1 ) and reset time Ti ( C00074/1 ) of the
I
max
controller.

Note!
V
min
boost is automatically calculated by the motor parameter identification using the
data specified on the motor nameplate so that a no-load current of approx. 0.8 I
rated
motor
results at the slip frequency of the machine.
V/f control (VFCplus + encoder)
If V/f control (VFCplus + encoder) is selected, we recommend a decidedly lower V
min
boost:
• In this case, select a V
min
boost which ensures that approx. 50 % of the rated motor
current flows at slip frequency when the motor is idling.
Parameter Info Lenze setting
Value Unit
C00073/1 VFC: Vp Imax controller 0.25
C00074/1 VFC: Ti Imax controller 65 ms