Lenze 8400 motec - Manual (Page 144)

5 Motor control (MCTRL)
5.9 Sensorless control for synchronous motors (SLPSM)
144 Lenze · 8400 motec · Reference manual · DMS 4.1 EN · 08/2013 · TD05
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Example: Voltage increase in the DC bus when field weakening is switched off
(For instance by an active setting of the controller inhibit or by tripping a fault or error at high motor
speed.)
[5-11] Example: Possible DC-bus voltage > 800 V if field weakening gets lost
Field weakening Speed n Motor voltage peak value
Switched off 4000 rpm 560 V
5700 rpm 800 V
6000 rpm 840 V
Switched-on 6000 rpm 560 V
• If pulse inhibit occurs at 6000 rpm and switched-on field
weakening, the DC bus is loaded to more than 800 V ().
• A speed limitation to 5700 rpm is required since this speed
causes a DC-bus voltage of 800 V if field weakening is
switched off.
n
U
4000
840 V
560 V
6000
> 800 V
Œ