Lenze 8400 StateLine - Manual (Page 200)

5 Motor control (MCTRL)
5.8 Sensorless control for synchronous motors (SLPSM)
200
Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
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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]
Œ

0 1500 3000 4500
Ž
0
1
n [rpm]
Parameter 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
Highlighted in grey = display parameter