Lenze i950

13.4.5 Set voltage boost
As an
alternave for the "Acvate voltage vector control (Imin controller)" funcon, a con-
stant, load independent voltage boost can be specied for low speeds (below the V/f rated
frequency) or for a motor standsll in order to opmise the starng performance.
WARNING!
Insucient cooling of the motor due to longer operaon at standsll.
If the motor is operated at standsll for a longer me - especially in case of smaller motors -
the mot
or can be destroyed by overtemperature!
▶
Connect the PTC thermistor (single sensor according to DIN 44081 or triple sensor according
to DIN 44082) or thermal contact (normally-closed contact) 4Motor temperature monitor-
ing. ^ 294
▶
Parameterise and acvate the 4Mot
or overload monitoring (i²*t). ^ 286
NOTICE
The voltage boost is added to the funcon 4Acvate voltage vector control (Imin control-
ler). ^ 241
Only se
t one of the two "boost" funcons.
Recommendaon: voltage vector control
For magnesing the motor, consider a sucient me from the controller enable
to the start of the speed ramp funcon generator. The bigger the motor the lon-
ger the me required for magnesaon. A motor with a power of 90 kW
requires up to 2 seconds.
Depending on the required starng torque, the voltage boost must be set so that the required
mot
or current will be available aer controller enable.
•
The v
oltage boost can be calculated by mulplying the stator resistance by the rated mag-
nesing current:
= ´Anlaufstrom ~ U R I
Boost s mN
0
0
U
Boost
0
0
U
Boost
Frequenz im Eckpunkt
Spannung im Eckpunkt Spannung im Eckpunkt
Frequenz im Eckpunkt
U
U
Boost
f
soll
U U
f
soll
U
0
0
0
0
•
Oponally, the voltage boost can be determined empirically by increasing the seng unl
the rated magnesing current ows.
•
The v
oltage boost is added geometrically to the voltage of the characterisc:
2 2
Kennlinie Boost
U= U U+
Parameter
Address Name / seng range / [default seng] Info
0x2B06 Voltage boost
0.0 ... [0.0] ... 100.0
V
Seng of the voltage boost for the voltage vector control.
Conguring the motor control
V
/f characterisc control for asynchronous motor (VFC open loop)
Set voltage boost
243