Lenze 8400 motec - Manual (Page 169)

Lenze · 8400 motec · Reference manual · DMS 4.1 EN · 08/2013 · TD05 169
5 Motor control (MCTRL)
5.12 Braking operation/brake energy management
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5.12.3.2 Degradation of braking energy by motor overmagnetisation
This function extension is available from version 02.00.00!
The braking procedure "6: Brake resistor and motor" to be selected in C00175 causes the motor to
be overmagnetised by the percentage value set in C00984 every time the speed is reduced. The
overmagnetisation causes the motor current to increase which leads to further losses in the motor
(and in the controller). Hence, the arising braking energy can be dissipated faster via the motor
losses.
Especially with smaller motors and their lower efficiency, the braking procedure allows for a quicker
braking than if no brake resistor was used and the brake ramp stopped time and again.
Example oscillogram
[5-18] Example oscillogram

Note!
The overmagnetisation may be selected only that high in C00984 that the maximum
inverter current will not be exceeded!
In case of high speeds, the controller may already output the maximum motor voltage
( C00090 ) and hence no increase of the motor voltage/motor magnetisation may be
possible.
Actual speed value
Motor current
DC-bus voltage
Motor voltage