Lenze 8240 frequency inverters - Manual (Page 40)

Commissioning
5-8 UOOu_^MTMO
L
5.4.2 Optimize control modes
5.4.2.1 Optimize motor-current control
Codes required
Code Name Possible settings IMPORTANT
Lenze Selection Info
C015 V/f-rated frequency 50.0 7.5 {0.1Hz} 960.0
C021 Slip compensation 0 0 {1 %} 20
C088 Rated motor current * 0.0 ... 1.2 ¡ rated output current * depends on
the unit Input only necessary
when motors not
C091 Motor cos j * 0.4 {0.1} 1.0
the unit when motors not
adapted.
Setting sequence
D
Drives with matching 4 pole standard motors 230/400 V in star connection do not need to be
adapted. After having started the drive, the controller itself detects all further motor data.
D
The following drives can be optimized by entering the nameplate data ”rated motor current” and
”cos
j” under C088 or C091:
- Motor one power class smaller than the motor assigned to the controller.
- Motor one or two power classes smaller than the motor assigned to the controller.
- Drives with 2, 6, 8, 10 and 12 pole standard motors.
- Drives with special motors.
D
With the slip compensation C021, you can optimize the ”sensorless speed control” for your
application.
1.If necessary, select C014 =
-4-.
(factory setting)
2.Select V/f-rated frequency
(C015).
Motor voltage Motor
connection
C015
220/380 V Y 52,6 Hz
230/400 V, 265/460 V, 280/480 V Y 50 Hz
220/380 V, 230/400 V, 265/460 V, 280/480 V D 87 Hz
380/660 V D 52,6 Hz
400/690 V D 50 Hz
3.If necessary, enter the motor
data of unadapted motors
(C088, C091).
4.Set slip compensation Rough setting by means of the motor data: p p
(C021):
л =
е
клуе − е к
е
клуе
⋅ NMMB
е
клуе =
С
Зк
⋅ SM
é
s Slip constant (C021)
n
rsyn
Synchronous motor speed [min -1 ]
n
r
Rated speed to motor nameplate [min -1 ]
f
dr
Rated frequency to motor nameplate [Hz]
p Number of pole pairs
Precise setting:
Change C021 under constant load until the speed is near the synchronous speed.
If C021 is set to too high values, the drive may become instable (overcompensation).
Important
D
The change from V/f-characteristic control to motor-current control should only be carried out
when the controller is inhibited.
D
The idle current of the motor (magnetizing current) must not exceed the rated current of the
controller.
D
With very small friction values it is possible that an angle offset of up to 180 ° occurs when
enabling the controller.
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