Lenze 8400 - Page 229

Lenze · 8400 HighLine · Reference manual · DMS 12.0 EN · 06/2017 · TD23 229
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
set in C00085
, C00089 and C00098. Then, the value is internally limited to 98 % of the set
maximum current (C00022
or maximally permissible current for the permanent switching
frequency set in C00018
).
• C00938
serves to limit the maximally effective field-producing motor current as well.
• In the Lenze setting, the field weakening for synchronous motors is active (C00079/4
).
However, the field-producing motor current is limited via C00938
to 30 % of the rated motor
current (C00088
). 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 C00938
.
 Standstill torque
 Rated torque
 Characteristic for continuous operation
 Limit characteristic at a 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]
Parameters Info Lenze setting
Value Unit
C00079/4 Field weakening 1: On
C00938
Limitation of maximally effective field-producing
motor current
• With regard to rated motor current (C00088
)
30 %
C00937/1 Maximally effective field-producing motor current - A
Greyed out = display parameter