Lenze 8400 TopLine - Manual (Page 167)

Lenze · 8400 TopLine · Reference manual · DMS 6.0 EN · 06/2014 · TD05/TD14
167
5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

How to set the V
min
boost:
1. Operate motor in idle state at approx. 6 % of the rated motor speed.
2. Increase V
min
boost ( C00016 ) until the following motor current is reached:
Motor in short-time operation up to 0.5 n
rated
• for self-ventilated motors: I
motor
≈ I
rated motor
• for forced ventilated motors: I
motor
≈ I
rated motor
Motor in continuous operation up to 0.5 n
rated
• for self-ventilated motors: I
motor
≈ 0.8 I
rated motor
• for forced ventilated motors: I
motor
≈ I
rated motor

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.
V/f control (VFCplus + encoder)
In case of operation in motor mode, we recommend a considerably lower Vmin boost
with V/f control (VFCplus + encoder) In this cas, the Vmin boost should be dimensioned
in such a way that in case of slip frequency in idle state, approx. 50 % of the rated motor
current flows.
In case of operation in generator mode, a light increase of the speed may be caused in
certain load ranges with V/f control (VFCplus + encoder) in the lower speed range. This
speed increase can be reduced by a higher V
min
boost.
The nBoost_a process signal is added to C00016 and can be used to implement different
V
min
boosts for operation in motor and generator mode. As an alternative, the
nVoltageAdd_a process signal can be used as well.