Lenze 8200 motec frequency inverter 0.25kW-7.5kW - Manual (Page 84)

Function library
Selection of control mode, optimisation of operating behaviour
7−13
L
EDB82MV752 EN 5.2
7.2 Optimising the operating behaviour
7.2.1 Slip compensation
Description
Under load, the speed of an asynchronous machine is reduced. This load dependent speed drop is
called slip. The slip can be partly compensated by setting C0021 accordingly. The slip compensation
is effective for all control modes (C0014).
Codes for parameter setting
Code Possible settings IMPORTANT
No. Name Lenze Selection
C0021 Slip compensation 0.0 −50.0 {0.1 %} 50.0 C0021 is calculated and stored under
C0148 when the motor parameters are
identified
^ 7−13
Automatic adjustment
The slip compensation is calculated during the motor parameter identification and entered under
C0021.
Preparing motor parameter identification
You must enter the motor data of the motor nameplate:
·
Rated motor speed (C0087)
·
Rated motor current (C0088)
·
Rated motor frequency (C0089)
·
Rated motor voltage (C0090)
·
Motor cos
j (C0091)
Motor parameter identification
Carry out the motor parameter identification. ( ^ 7−48 )
Automatically detected parameters
V/f−rated frequency (C0015), slip compensation (C0021) and motor stator inductivity (C0092) are
calculated and saved. The total resistance of motor cable and motor is measured and saved as motor
stator resistance (C0084).
Manual adjustment
The slip compensation must only be set if the motor parameter identification is not carried out. For
this purpose the slip compensation initially must be coarsely adjusted on the basis of the motor data.
The fine adjustment is made empirically during operation:
Coarse adjustment
1. Coarsely detect slip compensation and enter under C0021:
s +
n
rsyn
* n
r
n
rsyn
@ 100 %
n
rsyn
+
f
r
@ 60
p
s Slip constant (C0021) [%]
r
rsyn
Synchronous motor speed [min −1 ]
r
r
Rated motor speed to motor nameplate [min −1 ]
f
r
Rated motor frequency to motor nameplate [Hz]
p No. of pole pairs (1, 2, 3, ...) of the motor
s + 1500 min
*1 *1435 min *1
1500 min
*1
@ 100 % + 4.33 %
n
rsyn
+ 50Hz @ 60
2
+ 1500 min *1 Example for 4−pole motor / 1435 min −1 / 50 Hz:
Preset C0021 = 4.3 %