User guide

Lenze · 8400 BaseLine C · Reference manual · DMS 1.6 EN · 01/2014 · TD05 93
5 Motor control (MCTRL)
5.6 Parameterisable additional functions
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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 se-
lected, the switching frequency is reduced to the next frequency below when the heatsink tempe-
rature 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 fre-
quency is reached.
Switching frequency reduction due to high heatsink temperature can be deactivated via C144
. 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 "Error" 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 C018
, where the controller au-
tomatically lowers the switching frequency depending on the controller output current. The modu-
lation mode will not be changed. The changeover thresholds are included in the rated data of the
Hardware Manual (the Hardware Manual is available on the CD included in the scope of supply).
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 cor-
responding switching frequency. In case of larger load impulses, the overcurrent interruption may
be activated, to which the controller responds with "Error".
Limiting the maximum output frequency
The maximum output frequency (C910
) of the controller is not limited depending on the switching
frequency. Therefore, adapt the maximum output frequency according to our recommendation:
• At a switching frequency of 4 kHz, for instance, 500 Hz for the maximum output frequency
should not be exceeded.
Carry out further measures:
• If required, deactivate the switching frequency changeover by the heatsink temperature via
C144
.
• If required, ensure that the changeover threshold of the controller output current to the next
switching frequency below will not be exceeded. If required, select a constant switching fre-
quency in C018
.
Display of the current switching frequency
The current switching frequency applied in the controller is displayed in C725
.
Operation at an ambient temperature of 45°C
The controller is designed so that operation at an ambient temperature of 45° C without derating is
permissible at a switching frequency of 4 kHz.
Parameter Info Lenze setting
C144
Switching frequency reduction (temp.) 1: On
Maximum output frequency
1
8
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Switching frequency≤