Lenze EVF9383 - Manual (Page 170)

Operating mode
V/f characteristic control 6.8
6.8.1
l
6.8−6 EDSVF9383V EN 7.1−04/2012
Load−independent boost of the motor voltage for output frequencies below
the V/f rated frequency. This serves to optimise the torque behaviour.
C0016 must be adapted to the asynchronous motor used. Otherwise the
motor may be destroyed by overtemperature or the controller may be
operated with overcurrent:
1. Operate the motor in idle state at 5 ... 10 % of the rated speed (n
N
):
2. Increase V
min
until you reach the following motor current:
A Motor in short−time operation up to 0.5

n
N
:
– For self−ventilated motors: I
motor
»
I
N motor
– For forced ventilated motors: I
motor
»
I
N motor
B Motor in continuous operation up to 0.5

n
N
:
– For self−ventilated motors: I
motor
» 0.8
I
N motor
– For forced ventilated motors: I
motor
» I
N motor
)
Note!
Observe for all adjusting processes the thermal behaviour of the
connected asynchronous motor at low speeds:
ƒ Usually, standard asynchronous motors with insulation class B
can be driven for a short time with its rated current in the
speed range up to 0.5

n
N
.
ƒ Contact the motor manufacturer for getting the exact setting
values for the max. permissible motor current of
self−ventilated motors in the lower speed range.
0 1
0
C0089
C0090
100 %
N
n
n
U min
U
out
0 1
0
C0089
C0090
100 %
N
n
n
U min
U
out
9300vec085 9300vec086
Fig. 6.8−4 Umin boost at linear and square−law V/f characteristic
Set U
min
boost