Field Weakening For Synchronous Motors - Lenze 8400 StateLine C Reference Manual

5.9.9

Field weakening for synchronous motors

This function extension is available from version 11.00.00!

Note!
Function only available for sensorless control for synchronous motors (SLPSM)
(from version
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
[5-21] Voltage/speed characteristic with switched-on field weakening
[5-22] Calculation of the maximally reachable speed with switched-on field weakening
Firmware ≤ 11.00 - DMS 8.0 EN - 10/2011
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: info@clrwtr.com
10.00.00).
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 StateLine C | Reference manual
Parameterisable additional functions
( 236)
800V
⋅
------------------------------------- -
nenn_mot
2 U
⋅
nenn_mot
Motor control (MCTRL)
213