Lenze 8400 StateLine - Manual (Page 135)

Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
135
5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
5.4.3.2 Adapting the Vmin boost
The V
min
boost ( C00016 ) 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 C00016 .
The nBoost_a process signal at the SB LS_MotorInterface serves to carry out a V
min
boost as well:
The general linear and quadratic V/f characteristics are shown in the illustrations below. The
illustrations show the impacts of the parameters used to adapt the characteristic shape.
[5-5] Representation of the linear V/f characteristic (on the left) and quadratic V/f characteristic (on the right)

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
Identifier
DIS code | data type
Information/possible settings
nBoost_a
C00830/26 | INT
Process signal for the V
min
boost
• This signal is added to C00016 and has thus an increasing or decreasing effect.
• This signal serves to implement a load-dependent Vmin boost to improve the
torque behaviour in different load states, as for instance in case of operation in
generator or motor mode.
• Scaling: 16384 ≡ 100 % rated device voltage V
FU
(400 V or 230 V)

Stop!
Values selected too high may cause the motor to heat up due to the resulting
current!

Note!
The V
min
boost has an effect on output frequencies below the V/f base frequency
( C00015 ).
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