Field Weakening For Synchronous Motors - Lenze L-force HighLine C 8400 Series Reference Manual

5.10.9

Field weakening for synchronous motors

This function extension is available from version 11.00.00!

Note!
Function only possible with:
• Servo control (SC)
• Sensorless control for synchronous motors (SLPSM)
In the Lenze setting, the field weakening for synchronous motors is set in
C00079/4.
• If a high energy efficiency is required, keep the field weakening switched off
or restrict the field weakening operation via C00938.

Stop!
In the field weakening operation, a current is injected into the synchronous
motor even in idle state which can rise to maximum current (C00022).
Ensure that this no-load current does not cause the motor to be heated
impermissibly!
• We recommend using a temperature feedback via PTC or thermal contact.
U
motor
Œ
Armature control range
Field weakening range
[5-26] Voltage/speed characteristic with switched-on field weakening
[5-27] Calculation of the maximally reachable speed with switched-on field weakening
Firmware ≤ 11.00 - DMS 6.0 EN - 10/2011
Buy: www.ValinOnline.com | Phone 844-385-3099 | Email: CustomerService@valin.com
Motor temperature monitoring (PTC)
 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
n n
=
max
L
8400 HighLine C | Reference manual
Parameterisable additional functions
( 292)
800V
⋅
------------------------------------- -
nenn_mot
2 U ⋅
nenn_mot
Motor control (MCTRL)
(from version 10.00.00)
265