Lenze EVF9383 - Manual (Page 254)

Configuration
Function blocks
Internal motor control with V/f characteristic control (MCTRL1)
8
8.2
8.2.6
l
8.2−38 EDSVF9383V EN 7.1−04/2012
Suppressing no−load oscillations in case of:
ƒ Drives with different rated power of controller and motor, e. g. when
operating with high switching frequency and the power derating
involved.
ƒ Operation of higher−pole motors.
ƒ Operation of three−phase AC drives > 10 kW.
Compensation of resonances in the drive kit:
ƒ Certain asynchronous motors may show this behaviour above 1 /
3
of
the rated speed ( 1 /
3
× n
n
). This may result in an unstable operation
(current and speed variations).
Adjustment
The Lenze setting is designed for power−adapted motors.
Usually, the speed oscillations can be reduced by changing the Lenze setting
of the codes C0234 oder C0236 by the factor 2 ... 5.
1. Approach the range with speed oscillations.
2. Change the influence of the oscillation damping in C0234 (generally,
increase it).
3. Increase the limitation of the oscillation damping in C0236.
4. Change filter time in C0235 in the range of 1 ... 20 ms, if necessary.
ƒ These can be indicators for smooth running:
– Constant motor current characteristic
– Reduction of the mechanical oscillations in the bearing seat
Oscillation damping