Lenze 8400 BaseLine D - Manual (Page 85)

Lenze · 8400 BaseLine D · Reference manual · DMS 5.5 EN · 01/2014 · TD05
85
5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
5.4.3.2 Adapting the Vmin boost
The V
min
boost ( C016 ) of the motor voltage serves to select a load independent magnetising current
which is required for asynchronous motors. The torque behaviour of the motor can be optimised by
adapting the setting in C016 .
The general linear and quadratic V/f characteristics are shown in the illustrations below. The illust-
rations show the impacts of the parameters used to adapt the characteristic shape.
[5-3] Representation of the linear V/f characteristic (on the left) and quadratic V/f characteristic (on the right)

To set the V
min
boost, proceed as follows:
1. Operate motor in idle state at approx. 6 % of the rated motor speed.
2. Increase V
min
boost ( C016 ) until the following motor current is reached:
Motor in short-time operation up to 0.5 n
N
• for self-ventilated motors: I
Motor
≈ I
N Motor
• for forced ventilated motors: I
Motor
≈ I
N Motor
Motor in continuous operation up to 0.5 n
N
• for self-ventilated motors: I
Motor
≈ 0.8 I
N Motor
• for forced ventilated motors: I
Motor
≈ I
N Motor

Note!
The V
min
boost has an effect on output frequencies below the V/f base frequency ( C015 ).
C00015
C00016
C00015
2
C00016
2
V [V]
out
f [Hz]
V
(100 %)
rmot
1/N/PE AC 264 V
3/PE AC 264 V
3/PE AC 550 V
1/N/PE AC 180 V
3/PE AC 100 V
3/PE AC 320 V
C00015
C00016
V [V]
out
f [Hz]
V
(100 %)
rmot
1/N/PE AC 264 V
3/PE AC 264 V
3/PE AC 550 V
1/N/PE AC 180 V
3/PE AC 100 V
3/PE AC 320 V

Note!
V
min
boost is automatically calculated by the motor parameter identification using the
data specified on the motor nameplate so that a no-load current of approx. 0.8 I
rated
motor
results at the slip frequency of the machine.