Lenze E84DSxxx - Manual (Page 117)

Lenze · 8400 protec StateLine · Reference manual · DMS 4.2 EN · 03/2013 · TD05
117
5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
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5.4.2 Basic settings
The "Initial commissioning steps" listed in the table below are sufficient for a simple characteristic
control.
• Detailed information on the individual steps can be found in the following subchapters.

Tip!
Information on the optimisation of the control mode and the adaptation to the real
application is provided in chapter " Optimising the control mode ". ( 119)
Parameterisable additional functions are described correspondingly in the chapter
" Parameterisable additional functions ". ( 149)
5.4.2.1 Defining the V/f characteristic shape
In principle, three different characteristic shapes can be stipulated:
1. Linear V/f characteristic:
For drives for a constant, speed-independent load torque.
2. Quadratic V/f characteristic:
For drives with a load torque curve which is quadratic or in relation to speed. Quadratic V/f
characteristics are preferred in the case of centrifugal pumps and fan drives.
3. Freely definable V/f characteristic
For drives that require adaptation of the magnetising current by means of the output speed. The
freely definable V/f characteristic can be used e.g. for operation in conjunction with special
machines such as reluctance motors in order to suppress oscillations at the machine or to
optimise energy consumption.
[5-3] Principle of a linear V/f characteristic (on the left) and a quadratic V/f characteristic (on the right)
Initial commissioning steps
1. Defining the V/f characteristic shape . ( 117)
2. Defining current limits (Imax controller) . ( 118)
0 1
0
100 %
N
n
n
U min
U
out
0 1
0
100 %
N
n
n
U min
U
out