Defining The V/F Characteristic Shape - Lenze 8400 StateLine C Reference Manual

5.4.2.1

Defining the V/f characteristic shape

In principle, four 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.
100 %
[5-3] Principle of a linear V/f characteristic (on the left) and a quadratic V/f characteristic (on the right)
4. Linear V/f characteristic with voltage reduction
For drives which often work in partial load operation, the energy-saving V/f
characteristic control (VFCplusEco) offers the opportunity to reduce the voltage at low
load in order to save energy. At higher loads, the voltage reduction is cancelled and a
linear characteristic is caused.
The V/f characteristic shape is defined by selecting the corresponding motor control mode
in C00006:
V/f characteristic shape
Linear V/f characteristic
Square-law V/f characteristic
User-definable V/f characteristic
Linear V/f characteristic with voltage reduction

Tip!
• You can find detailed information on freely definable V/f characteristics in the
subchapter entitled
• You can find detailed information on the linear V/f characteristic with voltage
reduction in the chapter entitled
(VFCplusEco)".
Firmware ≤ 11.00 - DMS 8.0 EN - 10/2011
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: info@clrwtr.com
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"Defining a user-defined V/f
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8400 StateLine C | Reference manual
V/f characteristic control (VFCplus)
(from version 04.00.00):
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Motor control to be selected (C00006)
6: VFCplus: V/f linear
8: VFCplus: V/f quadr
10: VFCplus: V/f definable
11: VFCplusEco: V/f energy-saving
characteristic".
"V/f characteristic control - energy-saving
Motor control (MCTRL)
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