Lenze 8400 motec - Manual (Page 146)

5 Motor control (MCTRL)
5.10 Parameterisable additional functions
146 Lenze · 8400 motec · Reference manual · DMS 4.1 EN · 08/2013 · TD05
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Settable switching frequencies

Tip!
The Lenze setting
C00018 = 2 (8 kHz var./drive-opt.) is the optimal value for standard
applications.
Lowering the switching frequency due to high heatsink temperatures
Exceeding the maximally permissible heatsink temperature would lead to an inhibited drive due to
the "Overtemperature" error and a torquelessly coasting motor. Therefore, if the Lenze setting is
selected, the switching frequency is reduced to the next frequency below when the heatsink
temperature has risen to 5 °C below the maximally permissible temperature. After the heatsink has
cooled down, the controller automatically switches to the next frequency above until the set
switching frequency is reached.
Switching frequency reduction due to high heatsink temperature can be deactivated via
C00144 . If
the switching frequency reduction is deactivated, the "OH1: Heatsink overtemperature" error
message will be issued when the maximally permissible heatsink temperature is reached. An "Fault"
response is the result and the motor is coasting.
Lowering of the switching frequency depending on the output current
"Variable" switching frequencies can be selected for the controller in
C00018 , where the controller
automatically lowers the switching frequency depending on the controller output current. The
modulation mode will not be changed. The changeover thresholds are included in the "Rated data"
chapter of the Hardware Manual.
When a "fixed" switching frequency is selected, no switching frequency changeover takes place. In
case of fixed frequencies, the controller output current is limited to the permissible value of the
corresponding switching frequency. In case of larger load impulses, the overcurrent interruption
may be activated, to which the controller responds with "Fault".
Selection in C00018 Info
2 8 kHz var./drive-optimised • "var.": Adaptation of the switching frequency depending on the
current
• "drive-opt.": drive-optimised modulation ("sine/delta
modulation")
• "fixed": fixed switching frequencies
3 16 kHz var./drive-optimised
6 4 kHz constant/drive-optimised
7 8 kHz constant/drive-optimised
8 16 kHz constant/drive-optimised
23 16 kHz var/8 kHz min
Parameter Info Lenze setting
C00144 Switching frequency reduction (temp.) 1: On