Eaton M-Max series, Руководство по эксплуатации

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04/10 MN04020001Z-EN
Parameter menu (PAR)
111
U/f-characteristic curve (P11)
The frequency inverters of the M-Max™ series operate with a
sinusoidal pulse width modulation (PWM) in the inverter. The
IGBTs are actuated here by two V/f-based control procedures, that
you can select in parameter P11.8.
P11.8 = 0:
• Frequency control (Hz),
• Parallel connection of several motors,
• Large power difference (P
FU
>> P
Motor
),
• Switching in the output.
P11.8 = 1:
• Speed control (rpm, min
-1
) with slip compensation,
• Single operation (only one motor), maximum one power rating
smaller,
• High torque (requirement: exact motor data for the motor
calculation model).
The V/f characteristic (voltage/frequency characteristic) represents
a control procedure of the frequency inverter in which the motor
voltage is controlled in a specific ratio to the frequency. If the
voltage/frequency ratio is constant (linear characteristic), the
magnetizing flux and the torque behavior of the connected motor
is virtually constant.
In the standard application, the benchmark values for the
U/f-characteristic curve correspond with the rated operational
data of the connected motor (see ratings plate for the motor):
• Cut-off frequency P11.2 = Rated motor frequency
P7.6 = Maximum frequency P6.4.
• Output voltage P11.3 = Nominal motor voltage P7.5.
h The rating data of the U/f-characteristic curve is assigned
automatically and corresponds with the values of
parameter P7.5 (nominal motor voltage) and P7.6 (rated
motor frequency).
If you require other values for the U/f-characteristic curve,
you must first set parameters P7.5 and P7.6, before you
change the parameters of the U/f-characteristic curve
shown here.
PNU ID Access right
RUN Value Description Factory setting
(P1.3)
P11.1 108 - U/f characteristic curve 0
0 Linear
The output voltage changes linearly with the output frequency;
from zero to voltage P11.3 with the cut-off frequency P11.2.
By defining a minimum frequency (P6.3), a voltage corresponding
with one of the linear characteristic curves is output.
The U/f ratio running linearly between zero and the cut-off
frequency remains constant.
With parameter P11.6, the voltage value can be raised by
percentages in
a linear U/f-ratio over the entire manipulating range.
1 Quadratic
The output voltage changes quadratically with the output
frequency; from zero to voltage P11.3 with the cut-off frequency
P11.2.
By defining a minimum frequency P6.3, a voltage corresponding
with one of the quadratic characteristic curves is output. The U/f
ratio running quadratically between zero and the cut-off frequency
remains constant.
With parameter P11.6, the voltage value can be raised as a
percentage be a quadratic U/f ratio over the entire manipulating
range.
2 Parameterizable
In connection with parameters P11.4, P11.5 and P11.6, the U/f
ratio and therefore the parameters for characteristic curve
progress can be defined as required.