Lenze E94AxPExxxx - Manual (Page 254)

6 Motor interface
6.8 Parameterisable additional functions
254
Lenze · 9400 Servo PLC· Reference manual · DMS 4.0 EN · 11/2013 · TD05/06
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
6.8.2 Field weakening for synchronous machines
If required, the field weakening mode can be switched on in C00093 for synchronous machines.
[6-28] Voltage/speed characteristic with switched-on field weakening
[6-29] Calculation of the maximally reachable speed with switched-on field weakening
[6-30] Speed/torque characteristics of a synchronous servo motor with field weakening
• The maximally effective motor magnetising current is calculated based on the motor data set
in C00084 to C00091.Then the calculated value is internally limited to 98 % of the maximum
current set in C00022 .

Note!
Function only possible for servo control!
 Armature control range
 Field weakening range
• When field weakening is switched on, the motor
magnetising current is increased from 0 A to the maximally
effective magnetising current via an internal control loop
when the voltage limit is reached.
• As a result, a higher speed can be reached at the same
motor voltage or DC-bus voltage.
n Œ 
U
motor
n
max
n
nenn_mot
800V
2 U
nenn_mot
⋅
-------------------------------------- ⋅ =
 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]