Lenze E82xVxxxKxxxxx - Manual (Page 257)

Function library
Operating mode
V/f characteristic control
10
l
257 EDS82EV903 EN 3.0
10.2.1 V/f characteristic control
Description
The output voltage of the controller follows a defined characteristic. At low output
frequencies, the characteristic can be boosted. It can be adapted to different load profiles.
ƒ Linear characteristic for drives with constant load torque over the speed.
ƒ Quadratic characteristic for drives with quadratic load torque over the speed:
– Quadratic V/f characteristics are preferably used in centrifugal pump and fan
drives. However, it must be checked whether your pump or fan drive can be
operated in this operating mode!
– If your pump or fan drive cannot be used for the operation with a quadratic V/f
characteristic, the linear V/f characteristic or vector control mode must be used.
C0015
V [V]
out
f [Hz]
V
(100 %)
rmot
C0015
V [V]
out
f [Hz]
V
(100 %)
rmot
8200vec540 8200vec539
Fig. 10−2 Linear and square−law V/f characteristic
Codes for parameter setting
Code Possible settings IMPORTANT
No. Name Lenze Selection
C0014
v
Operating
mode 2 2 V/f characteristic control V ~ f
(linear characteristic with constant
V
min
boost)
l Commissioning is possible
without identifying motor
parameters
l Advantage of identification
with C0148:
– Improved smooth running at
low speeds
– V/f rated frequency (C0015)
and slip (C0021) are
calculated and saved. They do
not have to be entered
^ 255
3 V/f characteristic control V ~ f 2
(square−law characteristic with
constant V
min
boost)
4 Vector control In the case of the first selection
enter the motor data and identify
them with C0148
Otherwise commissioning is not
possible
When C0014 = 5, C0019 must be
set = 0 (automatic DC injection
brake is deactivated)
5 Sensorless torque control with speed
limitation
l Torque setpoint via C0412/6
l Speed limitation via setpoint 1
(NSET1−N1) if C0412/1 is assigned,
otherwise via maximum frequency
(C0011)