Lenze 8200 motec frequency inverter 0.25kW-7.5kW - Manual (Page 85)

Function library
Selection of control mode, optimisation of operating behaviour
7−14
L
EDB82MV752 EN 5.2
Fine adjustment
2. Correct C0021 during operation until no load−dependent speed drop occurs in the required
speed range between idle running and maximum motor load. The following is regarded as the
standard value for the correctly adjusted slip compensation:
– Deviation of the rated speed
£ 0.5 % for an output frequency of 5 ... 50 Hz (87 Hz)
– Greater deviations are possible in the field weakening range
)
Note!
If C0021 is set too high, the drive can get instable.
Tip
·
Set C0021 = 0.0 for speed control with internal process controller.
·
Negative slip (C0021 < 0) at V/f characteristic control causes a smoother" drive behaviour
with high load impacts or multi−motor applications.
7.2.2 Inverter switching frequency
Description
The switching frequency of the inverter influences the smooth running performance, the power loss
inside the controller, and the noise generation in the connected motor. The Lenze setting of 8 kHz is
the optimum value for standard applications. The following general rule applies:
The lower the switching frequency the
·
lower the power loss.
·
higher the noise generation.
Moreover you can determine whether the switching frequency is changed over to 4 kHz if the
heatsink temperature only amounts to approx. 5 °C below the permissible maximum temperature.
This serves to prevent the drive from being inhibited by the "overtemperature" error and the motor
from coasting without torque.
)
Note!
Note that when operating with a switching frequency of 16 kHz the output current
must be reduced to prevent the controller from being overheated (derating).
The current limit values (C0022 and C0023) must be adapted so that the currents
given in the technical data will not be exceeded.