Lenze i700 - Manual (Page 141)

Lenze · i700 servo inverter · Reference manual · DMS 1.5 EN · 03/2014 · TD05
141
5 Motor control & motor settings
5.14 Parameterising the V/f characteristic control
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5.14.3 Setting the voltage boost
As an alternative for the voltage vector control , a constant, load independent voltage boost can be
specified for low speeds (below the V/f rated frequency) or for a motor standstill in order to optimise
the starting performance.
Depending on the required starting torque, the voltage boost must be set so that the required
motor current will be available after controller enable.
• The voltage boost can be calculated by multiplying the stator resistance by the rated
magnetising current:
• Optionally, the voltage boost can be determined empirically by increasing the setting until the
rated magnetising current flows.
• The voltage boost is added geometrically to the voltage of the characteristic:
Subindex 2: VFC: Voltage vector controller - reset time
Reset time for voltage vector control
Setting range
(min. value | unit | max. value) Lenze setting
0.01 ms 2000.00 3.77 ms
 Write access  CINH  OSC  P  RX  TX Scaling: 1/100 UNSIGNED_32

Stop!
If the motor is operated at standstill for a longer time - especially in case of smaller
motors - the motor can be destroyed by overtemperature!
• Connect the KTY of the motor. Parameterise and activate the Motor temperature
monitoring . ( 250)
• Parameterise and activate the Monitoring of the motor utilisation (I²xt) . ( 241)
• Operate self-ventilated motors with a blower, if required.

Note!
The voltage boost acts additively to the voltage vector control .
• Only use one of the two "Boost" functions.
Recommendation: voltage vector control
Starting current V
Boost
∼ R
S
I
mN
⋅
=
U U
Characteristic
2
U
Boost
2
+ =