5motor control (mctrl) – Lenze 8400 User Manual
Page 217
Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
217
5
Motor control (MCTRL)
5.8
Sensorless control for synchronous motors (SLPSM)
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[5-19] Speed/torque characteristics of a synchronous servo motor with field weakening
Short overview of the relevant parameters:
• The maximally effective field-producing motor current is calculated based on the motor data
and
. Then, the value is internally limited to 98 % of the set
maximum current (
or maximally permissible current for the permanent switching
frequency set in
•
serves to limit the maximally effective field-producing motor current as well.
• In the Lenze setting, the field weakening for synchronous motors is active (
However, the field-producing motor current is limited via
to 30 % of the rated motor
current (
). Hence, the maximum speed is limited during field weakening operation
and, at the same time, the temperature rise of the motor during field weakening operation
and no-load operation is also limited.
• If a higher speed for the field weakening operation is required or the current in the field
weakening operation is to be limited (e.g. since no motor temperature detection is available
and/or heating in the field weakening operation is to be limited), the value must be increased
or reduced accordingly in
Standstill torque
Rated torque
Characteristic for continuous operation
Limit characteristic at mains voltage of 400 V without field weakening
Limit characteristic with field weakening
0
10
20
30
40
50
60
M [Nm]
0
1500
3000
4500
0
1
n [rpm]
Parameter
Info
Lenze setting
Value Unit
Field weakening
1: On
Limitation of maximally effective field-producing
motor current
• With regard to rated motor current (
30 %
Maximally effective field-producing motor current
- A
Highlighted in grey = display parameter